Video mirror system with compass

ABSTRACT

A video mirror system for a vehicle includes an interior rearview mirror assembly and a video display screen disposed in a mirror housing and behind a transflective mirror reflector of a transflective reflective element of the interior rearview mirror assembly. Information displayed by the video display screen is viewable by a driver of the equipped vehicle viewing through the transflective mirror reflector when the video display screen is activated and, when the video display screen is not activated, the presence of the video display screen behind the transflective mirror reflector is substantially not discerned by a driver of the equipped vehicle normally viewing the transflective reflective element when operating the equipped vehicle. A compass sensor may be disposed within the mirror housing and behind the transflective reflective element, and the compass sensor may adjust in tandem with adjustment of a rearward field of view of the transflective reflective element.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 11/363,415, filed Feb. 27, 2006, now U.S. Pat. No. 7,452,090,which is a continuation of U.S. patent application Ser. No. 10/456,599,filed Jun. 6, 2003, now U.S. Pat. No. 7,004,593, which claims thebenefit of U.S. provisional applications, Ser. No. 60/420,010, filedOct. 21, 2002; Ser. No. 60/398,240, filed Jul. 24, 2002; and Ser. No.60/386,373, filed Jun. 6, 2002, which are all hereby incorporated hereinby reference in their entireties.

FIELD OF THE INVENTION

The present invention relates generally to interior rearview mirrorassemblies for vehicles and, more particularly, to an interior rearviewmirror assembly which includes a compass system.

BACKGROUND OF THE INVENTION

Interior rearview mirror assemblies which include a directional orcompass display are known, such as the types disclosed in U.S. Pat. No.5,802,727, which is hereby incorporated herein by reference. Typically,such mirror assemblies include a compass sensor, such as amagnetoresistive sensor, a magnetocapacitive sensor, a magnetoinductivesensor, or a flux gate sensor or the like, which is fixedly attached tothe mirror mount that attaches the mirror assembly to a mirror assemblymounting element, such as a conventional mounting button mounted on aninterior surface of the windshield of the vehicle. The mirror assembliesalso include processing circuitry and a compass information display,typically included in the interior mirror casing (that includes themirror reflector) which is pivotally adjustable by the driver to suithis or her rearward field of view.

Predominantly, compass mirror assemblies in the market today involve thefixed placement of the compass sensor (and any locally associated sensorcircuitry), such as at the mirror mount where the mirror attaches to thewindshield or headliner of the vehicle. The compass system typicallyinvolves a cable/harness connection to the processing circuitry (whichis typically in the pivotable housing of the mirror assembly), which mayinclude the compass compensation circuitry and the like, which feeds orconnects to a display (such as a vacuum fluorescent (VF) display or thelike) that is typically included in the adjustable mirror casing (suchas behind the reflective element so as to display from behind andthrough the reflective element, or at an eyebrow or chin region of thebezel area of the mirror casing). The display then typically displays anoutput of the directional heading of the vehicle to the driver orpassenger of the vehicle, such as an eight octant display, such as N, S,E, W, NE, NW, SE, SW, or the like.

It has been proposed in the art to mount the compass sensor within themovable housing of the rearview mirror assembly. Processes have alsobeen proposed to compensate for movement of the sensor during normal useof the mirror, such as when the mirror head or casing is adjusted by thedriver. Such a commercially implemented system, such as currentlyimplemented in a Lexus vehicle and such as described in U.S. Pat. Nos.6,140,933 and 6,023,229, which are hereby incorporated herein byreference, requires the use of a specially adapted single ball mount orsingle pivot mirror assembly. Such compass mirror assemblies can becostly and often involve special tooling and complicated adaptation ofthe mirror assembly itself and the casing of the mirror assembly. Also,such compass systems as described in the patents referenced above arenot readily adapted for use with double ball or double pivot mirrorassemblies.

It is also known to provide a stand-alone compass pod or module, whichmay be mounted at the mirror assembly mount at the windshield orheadliner of the vehicle. The compass pod includes the compass sensor orsensors and all of the compass circuitry and is operable to output acompensated signal to a display at the instrument panel or console via acable or wire or the like. However, the display, typically a VF display,has its own logic, circuitry, drivers and/or photosensor input (foradjustment of the display in response to ambient lighting in thevehicle), which may not readily communicate with the circuitry output ofthe compass pod. In order to convey and/or receive the correctcompensated directional signal, a serial or similar encoding orcommunication protocol may need to be established, so that thecompensated directional signal is correctly received by the displayequipment in the instrument panel or console. This can result in anexpensive compass add-on device, since it may be costly to encode anddecode the signals from the compass circuitry.

It is also known to provide a compass display, and associated circuitry,all integrated into a module attaching to an interior rearview mirrorassembly, such as disclosed in U.S. Pat. No. 5,576,687, which is herebyincorporated herein by reference in its entirety. While such modules maywork well in many applications, such incorporation of the informationdisplay of compass direction/heading in the module has disadvantages,including the need to assure readability of the display by the driver ofthe vehicle.

It is also known in the art (such as disclosed in U.S. Pat. Nos.6,539,306; 5,724,316; and 5,761,094, which are hereby incorporatedherein by reference) to utilize a global positioning system as a meansof or adjunct to directional sensing in vehicles. Such known systemseither have or seek to overcome problems that can arise when the globalpositioning system fails to receive appropriate signal inputs fromorbiting satellites. Several potential solutions have been proposed thatcan involve costly and complicated additions to the vehicle.

Therefore, there is a need in the art for an economical interior compassrearview mirror assembly, and particularly an interior compass rearviewmirror assembly which is economical to use or implement, such that theassembly may be implemented in non-luxury vehicles, which often use adouble ball, prismatic interior rearview mirror assembly.

SUMMARY OF THE INVENTION

The present invention is intended to provide a low cost interiorrearview mirror system which includes a compass system having a displaywhich indicates the general direction in which the vehicle is traveling.The entire compass system, including the compass sensor, may be includedon a single printed circuit board positioned at or secured to a backsurface of the mirror reflective element, which may be a prismaticmirror reflective element (for low cost implementation), such that thecompass/mirror system may be readily installed in the casing of themirror assembly, and may be installed simultaneously (and with minimalif any additional labor involved) as the reflective element is includedin the mirror casing, such as snapped into or otherwise securedto/within the mirror casing.

According to an aspect of the present invention, an interior rearviewmirror assembly includes a double ball mounting arrangement, as is knownin the mirror art, for a casing and reflective element. The casing andreflective element are pivotable about a pair of pivots via the doubleball mounting arrangement. The mirror assembly includes a compasssystem, preferably entirely positioned within the casing and operable todisplay information regarding the directional heading of the vehicle toa driver of the vehicle.

In one form, the display includes ports or light transmissive regions orthe like, which are representative of only the four cardinal directionalpoints, such as, for example, the characters N, S, E, W, formed oretched in the reflective film coating of the reflective element (andforming a transparent window therein) using techniques such as disclosedin commonly assigned U.S. Pat. No. 4,882,565, issued to Gallmeyer onNov. 21, 1989, which is hereby incorporated herein by reference, and anillumination source within the casing and aligned with and behind eachof the characters. The appropriate illumination source or sources maythen be energized or illuminated to illuminate the appropriate characteror characters to or icons or indicia the driver to convey thedirectional heading information. For example, four individual lightemitting diodes may be placed behind and aligned with the respectivefour characters, so as to emit light through the characters for viewingby the driver of the vehicle.

According to another aspect of the present invention, an interiorrearview mirror system comprises an interior rearview mirror assembly,which includes a casing and a reflective element, and a compass system.The compass system includes a compass sensor and a display comprising aplurality of ports formed in the reflective coating of the reflectiveelement. The display includes a plurality of illumination sourcespositioned behind and aligned with respective ports. Each of theillumination sources is energized to project or emit illuminationthrough the respective port of the display. The illumination sources maybe mounted on a printed circuit board and the reflective element andprinted circuit board may be incorporated, such as by snapping intoplace, on or within the casing of the mirror assembly, with minimalinvasiveness to the casing and overall design and tooling of the mirrorassembly.

The display may include four illumination sources (preferably lightemitting diodes) mounted on the printed circuit board and with theprinted circuit board arranged behind the reflective element such thateach of the individual illumination sources is behind and aligned with arespective one of the ports (which may be formed as the characters N, S,E, W) formed or etched in the reflective coating of the reflectiveelement. Each of the illumination sources is positioned on the printedcircuit board such that it is aligned with, behind and emitting througha respective one of the four ports (that are preferably created on thereflective element itself). Optionally, and preferably, a light diffuserand/or a spectral filter may be interposed between the light source andthe rear of the reflective element. The compass processing circuitry(that typically includes digital circuitry including a microprocessorrunning compensation and other compass-related software) is operable toenergize or actuate one or more of the illumination sources to displaythe directional heading of the vehicle to the driver.

The printed circuit board may include a user actuatable button orbuttons, which are positioned to be accessible or to protrude throughone or more openings in the casing of the mirror assembly. The useractuatable button or buttons may be included in the unitary compasssystem, and may be operable to select a calibration mode/and or set azone setting of the compass system.

The compass system may be operable in conjunction with a globalpositioning system of the vehicle. The global positioning system may beoperable to detect or track movement of the vehicle to providepoint-to-point data of vehicle movement to determine a directionalheading of the vehicle. The global positioning system may be operable tocalibrate the compass system, indicate a zone in which the vehicle islocated, and/or provide a directional heading indication in situationswhere the compass sensor is adversely affected or compromised.

The present invention also provides a low cost compass system andcompass pod or module positionable at an interior rearview mirrorassembly, which includes a compass display for indicating the generaldirection in which the vehicle is traveling. The compass sensors andassociated circuitry are included within the compass pod or module,which is generally fixedly mounted to the mirror mount of the mirrorassembly. The compass pod includes a multi-wire cable which connects thecompass circuitry of the compass pod to the display in the mirrorassembly. The display is positioned at the rear surface of thereflective element of the mirror assembly and comprises a plurality ofillumination sources or devices positioned adjacent to or behindcorresponding ports, such as icons or characters or other indicia,etched or otherwise formed in the reflective surface or coating in thereflective element. Preferably, each display port is representative ofone of the four cardinal directional headings (N, S, E, W) or one of theeight cardinal and inter-cardinal directional headings (N, S, E, W, NE,NW, SE, SW), and the compass circuitry is operable to activate anappropriate illumination device at the display via providing power to anappropriate one of the wires connecting to the display. The mirrorassembly thus does not require much, if any, additional displaycircuitry, drivers or the like to encode or decode the signalcommunicated from the compass circuitry.

According to another aspect of the present invention, a compass systemfor a vehicle includes a compass module fixedly mountable at an interiorrearview mirror assembly of the vehicle and a display. The compassmodule comprises a compass sensor and compass circuitry. The compasscircuitry is operable to receive an input from the compass sensor and todetermine a directional heading of the vehicle in response to the input.The display is positioned remote from the compass module and comprises aplurality of illumination sources which are actuatable to projectillumination through corresponding ports which are indicative of adirectional heading. Each of the illumination sources has an associatedwire and is in electrical communication with the compass circuitry viathe respective associated wire, whereby the compass circuitry (or amicroprocessor or the like associated with the compass circuitry)provides electrical power to each of the illumination sources byenergizing the respective associated wire. The compass circuitry and/ormicroprocessor is/are operable to actuate or energize an appropriate oneof the illumination sources via the respective wire associated with theappropriate one of the illumination sources to indicate the directionalheading of the vehicle at the display.

The display may be positioned at a reflective element of a prismaticinterior rearview mirror assembly (for low cost implementation), suchthat the display may be readily installed in the casing of the mirrorassembly, and preferably installed simultaneously (and with minimal ifany additional labor involved) as the reflective element is included inthe mirror casing, such as snapped into or otherwise secured to/withinthe mirror casing. Alternately, the display may be positioned at areflective element of an electro-optic interior rearview mirrorassembly. In such applications, the compass module may includeelectro-optic reflective element automatic dimming/powering circuitryfor controlling the electro-optic reflective element, and may be inelectrical communication with the electro-optic reflective element via apair of wires. The microprocessor of the compass module thus may controlthe electro-optic reflective element via flowing electricity across thereflective element to darken the electrochromic medium as desired or inresponse to one or more photosensors.

The display and/or the compass module may include an ambient lightphotosensor for sensing the ambient light levels surrounding the mirrorassembly and/or the compass module. If the compass module is associatedwith a display positioned at an electro-optic interior rearview mirrorassembly, the display may include a glare detecting photosensor, whilethe compass module includes an ambient light photosensor.

According to another aspect of the present invention, an interiorrearview mirror system includes a compass pod mounted at a mirror mountof an interior rearview mirror assembly, which includes a casing and areflective element. The mirror mount and compass pod are generallyfixedly positioned relative to the vehicle, while the casing and thereflective element are pivotable or adjustable relative to the mirrormount. A compass display is positioned at the mirror reflective elementor casing and includes a plurality of illumination sources and at leastone port or light transmissive region formed in the reflective elementand corresponding to at least one of the illumination sources. Thecompass pod includes a compass sensor, a microprocessor and compasscircuitry, preferably substantially or entirely positioned within thepod and operable to provide an output signal to the display via aconnector cable to display information regarding the directional headingof the vehicle to a driver of the vehicle. Each wire of the connectorcable functions to provide power to an appropriate one or more of theillumination sources of the display in response to the microprocessorand/or compass circuitry energizing the respective wire.

The display may include four or eight illumination sources (preferablylight emitting diodes) arranged (such as mounted on a printed circuitboard) behind the reflective element such that each of the individualillumination sources is positioned behind and aligned with and emittinglight through a respective one of the ports formed or etched in thereflective coating of the reflective element. Optionally, andpreferably, a light diffuser and/or a spectral filter may be interposedbetween the light source and the rear of the reflective element. Themicroprocessor and/or compass processing circuitry (that typicallyincludes digital circuitry including a microprocessor runningcompensation and other compass-related software) is operable to energizeor actuate one or more of the illumination sources to display thedirectional heading of the vehicle to the driver.

Optionally, the display may comprise a multi-pixel or multi-elementreconfigurable display element. The multi-element display may comprisemultiple display elements and may be reconfigurable to displaydirectional heading information via selective activation of the displayelements.

The compass pod or module may include a printed circuit board positionedwithin the pod, with the compass sensor and compass circuitry positionedon the circuit board. The circuit board may also include a photosensorfor determining a level of ambient light at the pod and mirror assembly,whereby the compass circuitry may be operable to adjust the intensity ofthe illumination sources at the display in response to the photosensor.The circuit board may also include user actuatable buttons, such as acalibration switch or a zone switch, which are positioned to beaccessible or to protrude through one or more openings in the casing ofthe compass pod.

According to another aspect of the present invention, an interiorrearview mirror system comprises an interior rearview assembly (whichhas a mirror casing and a reflective element), a global positioningsystem of the vehicle, a magnetoresponsive sensor, a microprocessor, anda display. The global positioning system generates locational data andthe magnetoresponsive sensor generates direction indicative signals. Themicroprocessor processes at least one of the locational data and thedirection indicative signals and generates directional headinginformation indicative of the directional heading of the vehicle. Thedisplay is associated with or adjacent to the interior rearview mirrorassembly and is viewable by the driver of the vehicle. The displaydisplays the directional heading information. The microprocessortemporarily processes the direction indicative signals generated by themagnetoresponsive sensor to generate the directional heading informationwhen the locational data generated by the global positioning system iscompromised, thereby ensuring consistency of the directional headinginformation being displayed.

Optionally, the microprocessor may process the locational data and/orother data generated by the global positioning system of the vehicle toextract or derive other data or information for displaying to the driveror occupant of the vehicle. The display may selectively display suchother data or information to the driver or occupant of the vehicle.

Therefore, the present invention provides a low cost compass system foran interior rearview mirror assembly which provides the compass sensorand compass circuitry at a generally fixedly mounted pod or module. Thecompass sensor and circuitry may be part of a single printed circuitboard, which may be secured within the pod or module, while the displayand illumination sources are mounted at the rear of the reflectiveelement. Each illumination source of the display may be activated via asimple power signal from the microprocessor and/or compass circuitry viaa respective wire of a connector cable between the compass pod and thedisplay, without requiring any encoding or decoding of the signal fromthe compass circuitry in order to provide the correct display to thedriver of the vehicle. The present invention thus provides a low costcompass system with minimal associated encoding or decoding costs anddesign modifications, and with minimal special adaptation of the mirrorcasing.

The present invention may also provide a low cost, double ball mountedinterior rearview mirror assembly which includes a compass system withinthe mirror casing. The compass system may be part of a single printedcircuit board, which may be secured to the rear of (or disposed to therear of) the reflective element, such that the compass system may beeasily installed in the mirror casing when or after the reflectiveelement is snapped into the casing. The circuit board may include aplurality of illumination sources which are positioned generallyadjacent to ports or light transmissive regions formed in the reflectiveelement, such that when each of the illumination sources is energized,the illumination source projects illumination through the respectiveport to provide direction information or other information to a driveror occupant of the vehicle. The compass system may be implemented atand/or within a casing of an interior rearview mirror assembly withminimal modifications being necessary to the casing. The presentinvention thus provides a low cost compass system with minimalassociated tooling costs and design modifications, and with minimalspecial adaptation of the mirror casing, for example.

Optionally, the mirror system of the present invention may provide aGPS-derived compass system which is operable to deduce directionalheading information and display the directional heading information to adriver or occupant of the vehicle. The mirror system may include amagnetoresponsive sensor which may function as an auxiliary or back upto the GPS-derived compass system when the global positioning system ofthe vehicle is not generating an appropriate signal or input to theGPS-derived compass system. The auxiliary magnetoresponsive compasssensor thus ensures consistency of the directional heading informationbeing displayed. Because the GPS-derived compass system may function asthe primary compass system and may function to calibrate themagnetoresponsive sensor, compass control circuitry and calibrationalgorithms and circuitry are not required.

These and other objects, advantages, purposes and features of thepresent invention will become apparent upon review of the followingspecification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a forward facing elevation of an interior rearview mirrorassembly in accordance with the present invention, as facing forwardwith respect to a direction of travel of a vehicle;

FIG. 2 is a side elevation of the interior rearview mirror assembly ofFIG. 1;

FIG. 3 is a sectional view of the mirror assembly taken along the lineIII-III in FIG. 1;

FIG. 4 is a forward facing elevation of another interior rearview mirrorassembly in accordance with the present invention, as facing forwardwith respect to a direction of travel of a vehicle;

FIG. 5 is a sectional view similar to FIG. 3 of an interior rearviewmirror assembly in accordance with the present invention;

FIG. 6 is a flow diagram of a compass calibration process in accordancewith the present invention;

FIG. 7 is a side elevation and partial sectional view of a compasssystem in accordance with the present invention, with a compass modulemounted at an interior rearview mirror assembly of a vehicle;

FIG. 7A is a forward facing elevation of the mirror assembly of FIG. 7;

FIG. 8 is a side elevation and partial sectional view of another compasssystem in accordance with the present invention, with a compass modulemounted on a prismatic interior rearview mirror assembly of a vehicle;

FIG. 8A is a forward facing elevation of the mirror assembly of FIG. 8;

FIG. 9 is a side elevation and partial sectional view of another compasssystem in accordance with the present invention, with a compass modulemounted on an electro-optic interior rearview mirror assembly of avehicle;

FIG. 9A is a forward facing elevation of the mirror assembly of FIG. 9;

FIG. 10 is a side elevation and partial sectional view of anothercompass system in accordance with the present invention, with a compassmodule mounted on an electro-optic interior rearview mirror assembly ofa vehicle;

FIG. 10A is a forward facing elevation of the mirror assembly of FIG.10;

FIG. 11 is a side elevation and partial sectional view of anothercompass system in accordance with the present invention, with a compassmodule mounted on an electro-optic interior rearview mirror assembly ofa vehicle;

FIG. 11A is a forward facing elevation of the mirror assembly of FIG.11;

FIG. 12 is a side elevation and partial sectional view of anothercompass system in accordance with the present invention, with a compassmodule mounted on an electro-optic interior rearview mirror assembly ofa vehicle;

FIG. 12A is a forward facing elevation of the mirror assembly andcompass module of FIG. 12;

FIG. 13 is a side elevation and partial sectional view of a mirrorsystem in accordance with the present invention, having a GPS-derivedcompass system, and with the information display being positioned at theaccessory module;

FIG. 14 is a side elevation and partial sectional view of another mirrorsystem in accordance with the present invention, having a GPS-derivedcompass system, with a wireless data communication between the accessorymodule and the mirror assembly; and

FIG. 15 is a side elevation and partial sectional view of another mirrorsystem similar to the mirror system of FIG. 14, with the informationdisplay positioned at the bezel portion of the mirror assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings and the illustrative embodiments depictedtherein, a compassized prismatic interior rearview mirror assembly orsystem 10 includes a double pivot or double ball mounting arrangement 12for pivotally or adjustably mounting a casing 14 and prismaticreflective element 16 of mirror assembly 10 relative to an interiorportion of a vehicle, such as to an interior surface of a windshield(not shown) of a vehicle (FIGS. 1-3) or the like. The mirror assembly 10includes a compass system 18, which includes a compass sensor (notshown) and a display 20 for providing a display or indication of thedirectional heading of the vehicle at the reflective element 16 of themirror.

As shown in FIG. 2, the double ball or double pivot mirror mountingarrangement 12 includes a mounting arm 12 a which is pivotally mountedat opposite ends to a mirror mount 12 b (mounted at the windshield orheadliner of the vehicle, such as at a mounting button at the interiorsurface of the vehicle) and a mirror casing mount 12 c. An example of adouble pivot or double ball mounting arrangement is disclosed incommonly assigned U.S. Pat. Nos. 4,646,210 and 6,331,066, which arehereby incorporated herein by reference. Preferably, the mirror mountingcomponents provide a breakaway type connection or mount, such as thetypes disclosed in U.S. Pat. Nos. 6,172,613; 6,087,953; 5,820,097;5,377,949; and/or 5,330,149, which are hereby incorporated herein byreference.

The prismatic reflective element 16 may be formed from various materialssuch as plastic or glass, but preferably is glass, and preferably has aplanar front surface 16 a extending at an angle to a planar rear surface16 b (FIG. 3). Rear surface 16 b is preferably coated with a reflectivelayer of metal such as chromium, aluminum or alloys thereof as isconventionally known in the industry. The mirror casing 14 is pivotablerelative to mounting arm 12 a and mirror mount 12 b to pivot thereflective surface 16 b in order to reduce glare during nighttimeconditions. When the mirror casing is pivoted from a full reflectivityday position to a reduced reflectivity night position, the reflectivesurface 16 b is rotated clockwise such that the uncoated front surface16 a is aligned for viewing by the vehicle driver instead of reflectivesurface 16 b. Preferably, reflective surface 16 b reflects at leastabout 60% to 95% of the light incident thereon, while uncoated frontsurface 16 a reflects about 4% of the light incident thereon, therebysignificantly reducing glare from headlights or other bright lightsrearward of the vehicle to the driver's eyes. Although shown anddescribed as having a prismatic reflective element, it is envisionedthat the present invention may be equally suitable and applicable toelectro-optic or electrochromic interior rearview mirror assemblieshaving electro-optic or electrochromic reflective elements.

The compass sensor of compass system 18 functions to detect adirectional heading of the vehicle relative to the earth's magneticfield, as is known in the art. The compass sensor may be any knownsensor type, such as a magnetoresistive sensor (such as described inU.S. Pat. No. 5,802,727, and U.S. patent application Ser. No.09/540,702, filed Mar. 31, 2000 by Schierbeek et al. for VEHICLE COMPASSCOMPENSATION, now U.S. Pat. No. 6,513,252, which are hereby incorporatedherein by reference), a magnetocapacitive sensor, a magnetoinductivesensor, or a flux-gate sensor or the like, without affecting the scopeof the present invention. The compass sensor may include a pair ofsensors positioned generally orthogonal to one another. The pair ofgenerally orthogonal sensors are preferably oriented relative to thevehicle such that one of the sensors is generally parallel to the floorof the vehicle and pointing generally forwardly in the direction oftravel of the vehicle, while the other is generally orthogonal orperpendicular to the first sensor. The compass sensor or sensors providean output signal to compass processing circuitry, which is operable toprocess the output signal to determine the vehicle heading and toactuate or control or adjust an output of display 20 in response to theoutput signal.

As shown in FIG. 3, compass system 18 may include a printed circuitboard (PCB) 22, which may be mounted or positioned or bonded along therear surface 16 b of the reflective element 16, as shown in FIG. 3. Theprinted circuit board 22 may include all of the processing circuitry andthe compass sensor. Such processing circuitry may include compensationmethods known in the art, such as described in U.S. Pat. Nos. 4,546,551;5,699,044; 4,953,305; 5,576,687; 5,632,092; 5,644,851; 5,708,410;5,737,226; 5,802,727; 5,878,370; 6,087,953; 6,173,501; and 6,222,460,and U.S. patent application Ser. No. 09/999,429, filed Nov. 15, 2001 byDeLine et al. for INTERIOR REARVIEW MIRROR SYSTEM INCORPORATING ADIRECTIONAL INFORMATION DISPLAY, now U.S. Pat. No. 6,642,851, andEuropean patent application, published Oct. 11, 2000 under PublicationNo. EP 0 1043566, which are all hereby incorporated herein by reference.

Because the mirror casing and reflective element may be pivoted to beangled generally toward the head of the driver of the vehicle, such as,for example, approximately 22 degrees toward the driver side of thevehicle and approximately 6 degrees downward, the compassized interiorrearview mirror assembly of the present invention may be adapted tomount the compass sensor or sensors on a physical mount at the printedcircuit board which compensates for or approximates and effectivelycancels the approximate angle of the mirror casing so as to orient thecompass sensors generally in the desired orientation, even when themirror casing and reflective element are angled toward the driver of thevehicle. Optionally, the printed circuit board may be mounted at aphysical mount at the reflective element to accommodate the approximateangle of the mirror casing. The physical mount may be a wedge shapedmounting element or bracket or any other means for orienting the sensorsrelative to the reflective element to accommodate for the typical angleof tilt of the mirror head toward a driver of a vehicle. The typicalangle or tilt of the mirror head or casing may be calculated orotherwise determined or approximated and the physical mount may then beformed to compensate or cancel the typical angle of the mirror. Thedesired mounting orientation may vary depending on the particularvehicle in which the compassized mirror assembly is being installed,since the mirror assembly may be mounted at different heights along thewindshield or at the headliner of different vehicle models. In lieu of aphysical orientation as described above, software compensation, as knownin the art, can be used to negate or cancel out the above effects.

As shown in FIG. 1, display 20 provides a display region 20 a at thereflective element 16 which includes ports or portions 20 b, which maycomprise icons, characters or letters or the like representative of onlythe cardinal directional points 20 b, such as, for example, thecharacters N, S, E, W, formed or etched in the reflective film coatingof the reflective element (and forming a transparent window therein).Display region 20 a provides an indication of N, S, E, W information onreflective element 16, and may be positioned at an upper right handquadrant of the reflective element (although the display region may bepositioned elsewhere on the reflective element, without affecting thescope of the present invention). The characters or letters N, S, E, W(or other icons or indicia) may be sandblasted or laser created orchemically etched or otherwise applied or formed on the rearward surfaceof the reflective element, such as via techniques such as disclosed incommonly assigned U.S. Pat. No. 4,882,565, issued to Gallmeyer on Nov.21, 1989, which is hereby incorporated herein by reference. Optionally,however, the display of the present invention may be a display on demandtype of display, such as disclosed in commonly assigned U.S. Pat. Nos.5,668,663 and 5,724,187, and U.S. patent application Ser. No.10/054,633, filed Jan. 22, 2002 by Lynam et al. for VEHICULAR LIGHTINGSYSTEM, now U.S. Pat. No. 7,195,381; and Ser. No. 09/793,002, filed Feb.26, 2001, entitled VIDEO MIRROR SYSTEMS INCORPORATING AN ACCESSORYMODULE, now U.S. Pat. No. 6,690,268, the entire disclosures of which arehereby incorporated by reference herein, without affecting the scope ofthe present invention.

Display 20 also includes four illumination sources 24, such as lightemitting diodes (LEDs), such as described in U.S. patent applicationSer. No. 10/054,633, filed Jan. 22, 2002 by Lynam et al. for VEHICULARLIGHTING SYSTEM, now U.S. Pat. No. 7,195,381, which is herebyincorporated herein by reference, or any other light emitting devices,positioned behind and aligned with respective or corresponding ones ofcharacters or ports or icons or indicia or points 20 b (such as lettersN, S, E, W). Optionally, the printed circuit board 22 may include theillumination sources or light emitting diodes 24 positioned thereon.Each illumination source 24 is positioned behind the reflective elementand generally aligned with the characters or icons 20 b of the display.Each illumination source 24 may be energized, either alone or incombination with one or more of the other illumination sources, toprovide illumination of the respective port or ports or icon or icons 20b of display region 20 a, such that the ports or characters or compassicons are backlit by the respective illumination sources, in order toconvey directional information or other information (discussed below) tothe driver of the vehicle. A seal or sealant may be provided between thecircuit board 22 and the reflective element 16 and may generallysurround each light source or port or icon and/or may separate orisolate each light source or port from the other light sources/ports tolimit or substantially preclude light emitted by one light source (andthus emitted through a corresponding port) from also emitting throughone or more of the other ports or icons of the display.

The ports 20 b of display 20 may comprise any form of port or viewopening or an at least partially light transmissive portion of thereflective element 16, and are at least partially transmitting, andpreferably substantially light transmitting, as compared to thesurrounding area of the reflective element. The ports thus may transmitillumination emitted by the illumination sources 24 through reflectiveelement 16 for viewing by the driver or occupant of the vehicle. Theports may be formed on the reflective element via any manner, such as,for example, via etching or ablating the reflective coating or surfacefrom the rear surface of the reflective element, or the ports may bedefined as part of display on demand areas or the like forelectrochromic reflective elements (or transflective electrochromicreflective elements), or the ports may comprise any other at leastpartially light transmitting regions formed on a prismatic reflectiveelement or an electro-optic reflective element, without affecting thescope of the present invention. The ports may be formed in any desiredshape, such as characters, letters, icons, symbols or other indicia orthe like, and preferably may be representative or indicative of thedirectional heading of the vehicle. It is further envisioned that theillumination sources may define a multi-pixel reconfigurable displayelement, whereby the individual illumination sources or pixels may beilluminated or energized individually or in various combinations toconvey the desired information, as discussed below.

The reflective element 16 may also include a port or aperture or hole 20c in the center area or region of the display area 20 a to accommodate aphoto detector or sensor (not shown), such as a photo transistor, aphoto resistor, a photo diode or the like, which may be operable tosense the ambient light levels surrounding the mirror assembly or thelight from headlights of vehicles rearward of the subject vehicle. Thephotosensor may be positioned or mounted on the printed circuit board 22and may be positioned, aligned and directed to receive illuminationthrough the aperture or hole 20 c in the reflective element coating atthe display region 20 a or elsewhere on reflective element 16 or casing14 (such as through an opening formed in a wall of the casingimmediately adjacent to the location of the photosensor). Thephotosensor is operable to detect the ambient light levels generallysurrounding the mirror assembly to provide for dimming of the output ofdisplay 20 in darkened lighting conditions, such as at nighttimeconditions, in order to reduce the intensity of display 20 to reduceglare and distraction and annoyance to the driver of the vehicle.Optionally, such dimming of the display may be performed in response toan instrument panel dimming system of the vehicle, without affecting thescope of the present invention. The printed circuit board may includeother electronic components, such as integrated circuits, resistors,capacitors, diodes and/or the like.

Compass system 18 includes processing circuitry which is operable toactuate or energize one or more of the illumination sources 24 inresponse to an output from the compass sensor. For example, theillumination source behind the letter N may be energized or actuatedwhen the vehicle is heading generally Northward and within a particularrange of Northward, while the illumination sources behind both of theletters N and E may be energized or actuated when the vehicle is headingin a direction generally between North and East. Each respective one ofthe illumination sources is illuminated when the vehicle is within apredetermined range of the particular direction at the respectivecardinal point (N, S, E, W). The combination of two adjacent energizedillumination sources (e.g. the illumination sources behind and alignedwith the N and the E characters), such that two characters are backlitby the energized or illuminated illumination sources, indicates aheading between the two cardinal points, such as within a range aboutthe intercardinal points (northeast, northwest, southeast, southwest).Optionally, the compass system of the present invention may give greaterweight (or a broader band or range) to the cardinal octant points andless weight (or a narrower band or range) to the intercardinal points.However, other bands or ranges may be implemented, such as a typical 45degree band or range about each octant point, without affecting thescope of the present invention.

Thus, the compass mirror system of the present invention may provide adisplay of directional information using only four individualillumination sources, such as four light emitting diodes. The fourillumination sources are operable to convey directional information forall eight directional headings by activating or energizing an individualillumination source or a combination of two adjacent illuminationsources (by adjacent, it is meant the adjacent directional beadingpoints, such as N and E; E and S; S and W; and W and N). Thus, economyis achieved via implementation of only four illumination sources, whilethe directional heading of the vehicle is conveyed within a range ofeach of the eight cardinal and intercardinal directional headings orpoints.

Additionally, the processing circuitry may be operable to activate oneor more of the illumination sources 24 to convey other information tothe driver of the vehicle via display 20. For example, if the compasssystem is in a calibration mode, one or more, or all four, of theillumination sources may be illuminated or may flash until thecalibration of the compass system is complete (clearly, othercombinations of illumination may be implemented, without affecting thescope of the present invention).

Also, the compass system may be operable to convey informationpertaining to the calibration or zone setting mode for a particular zonein which the vehicle is located via display 20. The zones are regions orzones which indicate to the processing circuitry the appropriatecompensation for the compass sensor, depending on the vehicle'slocation, as is known in the compass art (typically, 1-15 differentzones may be desired or selected). The display may convey the zonechosen via a code or map by illuminating or energizing one of theillumination sources and/or two or more of the illumination sources indifferent combinations or codes. The zone code may be included in theowner's manual of the vehicle so the driver of the vehicle may decipherthe code being illuminated on the display. For example, the port orcharacter representative of a North heading indication (e.g., thecharacter N) may be illuminated (and intermittently illuminated orflashed, if desired) if the vehicle is in zone 1, while the character Emay be illuminated if the vehicle is in zone 2; S may be illuminated ifthe vehicle is in zone 3; and W may be illuminated if the vehicle is inzone 4. Additionally, a combination of characters may be illuminated orflashed to indicate that the vehicle is in other zones. For example, Nand E may be illuminated or flashed when in zone 5; N and S may beilluminated when in zone 6; N and W may be illuminated when in zone 7; Eand W may be illuminated when in zone 8; E and S may be illuminated whenin zone 9; W and S may be illuminated when in zone 10; N and E and S maybe illuminated when in zone 11; N and S and W may be illuminated when inzone 12; E and S and W may be illuminated when in zone 13 and all four(N, E, S and W) may be illuminated when in zone 14. The individualillumination or combination of illuminated or flashed display charactersmay thus be selected to provide a distinct display for each particularzone that the vehicle may be positioned in. The illumination source orsources may be continuously or intermittently energized or activated toconvey the zone information to the driver of the vehicle.

Optionally, display 20 may include an additional indicator or indicators(not shown), such that when the additional indicator is illuminated, themeaning of or the information conveyed by the combination of displayports or characters being illuminated changes to a second set ofmeanings, in order to double the amount of information that may beconveyed by the display 20 of the compass system of the presentinvention. It is envisioned that other information may be conveyed viadisplay 20 and optionally one or more additional indicators may beprovided, without affecting the scope of the present invention. It isfurther envisioned that the display may be actuated to illuminate onlycombinations of ports or characters which are not compass headings (suchas activating the illumination sources behind and generally aligned withthe characters N and S; E and W; N and E and S, and the like) to conveynon-directional related information, in order to reduce the possibilityof confusion to the driver upon seeing illumination of directionalheadings, such as illumination of one port or character or adjacentports or characters only, such as illumination of the N and E characterstogether.

Because the compass system of the present invention may be implementedas part of a low cost prismatic mirror assembly, the initial mirrorassembly application may not have a power supply connected thereto (suchas a connection to a 12 volt battery power source of the vehicle or thelike). The power supply connector may be provided from the headliner ofthe vehicle and may connect to a connector at or within the mirrorcasing which houses the compass system in accordance with the presentinvention. The mirror casing may be formed or may be adapted to providean opening for connection of the wire harness to the compass systemwithin the casing.

The compass system of the present invention may be implemented as partof an interior rearview mirror assembly supplied to a vehiclemanufacturer and installed in a particular vehicle which includes acompass mirror option. It is further envisioned that the compass systemmay be supplied to a mirror assembler or supplier as a kit. The kit mayinclude a printed circuit board having an electrical connector, acompass sensor, and illumination sources for the display, and may or maynot include the reflective element having the characters sandblasted,etched or otherwise formed thereon. The mirror assembler may purchasethe compass kit (and attach the kit to an adapted reflective element) orcompassized reflective element and may install the reflective elementand compass kit into the housing or casing of the mirror assemblies. Anoperator thus may incorporate, such as via popping or snapping, thecompassized reflective element into the casing with minimal extracustomization and cost to the casing and thus to the overall mirrorassembly. The printed circuit board of the compass system may be sizedto fit within the interior space of standard casings, such that minimalchanges or modifications to the casing are necessary. For example, thecase may be modified or made to have an access hole for accessing acalibration button or other button or buttons or the like (such as forinitiating calibration of the compass system if needed or to set a zoneof the compass system as needed, as is known in the mirror art), and/ora hole or opening for a power supply connection or the like, but mayotherwise be the same as for noncompassized mirror assemblies. Thus, forexample, a wiring harness with a plug connector can extend down from theheadliner of the vehicle and pass through the hole in the mirror casingand connect directly to the printed circuit board on the back of thereflective element. Correspondingly, the owner or driver of the vehiclemay access one or more user control buttons (such as for manualactuation of a compass calibration mode or the like) through openings inthe casing, such as with their finger, a pen or other instrument or thelike. Preferably, any such openings may be provided on the casing foraccessing connectors and buttons and the like on the printed circuitboard at the back of the reflective element.

For example, if the compass system is positioned generally at an upperquadrant or portion of the mirror assembly (or around an edge of themirror assembly), a wire harness may extend down from the headliner ofthe vehicle to the compass system within the casing of the mirrorassembly, whereby the casing of the mirror assembly may include one ormore openings or holes for the wire harness and for access to the buttonor buttons of the compass system (the casing may optionally include anopening for a photosensor as well). The hole or holes may be formed bythe mirror assembler or manufacturer to adapt an existing casing for usewith the compassized reflective element of the present invention.Alternately, the compass system may include a lead or wire extendingfrom the casing of the mirror assembly which is connectable to aconnector at the wire harness of the vehicle, without affecting thescope of the present invention. The printed circuit board and reflectormay snap into the mirror casing so any buttons and/or wire connectorsalign with the corresponding holes in the casing. The compass system ofthe present invention is thus minimally invasive or not at all invasiveto the overall interior rearview mirror assembly design.

The mirror manufacturer may mold the casing or housing and snap thebracket assembly, pivot and/or ball member and/or toggle assembly, andother known components of the mirror assembly, into the casingsubstantially immediately after molding or heating of the casing andwhile the casing is still warm and pliable. The reflective element andassociated compass system may also then be snapped into the casing whileit is warm to ease assembly of the compassized mirror assembly.Accordingly, the mirror manufacturer may assemble a prismatic mirrorwith a compass system via snapping the compassized reflective element ofthe present invention into an existing (and maybe modified) mirrorcasing. The manufacturer of the compassized reflective element may thenbe able to optimize the size and design and layout and attachment of theprinted circuit board for the desired area of the mirror casing, such asthe upper right hand quadrant of the mirror (as shown in FIG. 1). Themirror manufacturer may mold the casing to accommodate the compassizedreflective element with minimal modifications required, and may easilymold separate casings for mirrors with and without compass systems, suchas by molding one casing with an opening or openings for wiring andbutton access and one without any such openings.

An embodiment of the present invention which may be included in alighted interior prismatic assembly and successfully used in anautomobile is shown in FIG. 4, where an interior mirror system orassembly 40 includes prismatic mirror reflector element 42 included inmirror casing 44. A printed circuit board (not shown in FIG. 4), towhich a magnetoresponsive compass direction sensing sensor may bemounted (including microprocessor-based compass processing circuitry),may be disposed to the rear of reflector element 42. The compasscircuitry may include algorithmic routines for compass calibrationand/or compensation, such as are described in U.S. patent applicationSer. No. 09/540,702, filed Mar. 31, 2000 by Schierbeek et al. forVEHICLE COMPASS COMPENSATION, now U.S. Pat. No. 6,513,252, the entiredisclosure of which is hereby incorporated by reference herein). Thesilver mirror reflector coating (and its associated copper protectivelayer and paint protective layer/layers) on the rear surface ofreflector element 42 may be removed by a laser etching/ablating tocreate the ports or light transmitting regions, such as the N, E, S, Wtransparent/light transmitting indicia/icons 46 a, 46 b, 46 c, 46 d,respectively. A central transparent/light transmitting central region 48may also be created. Although shown and described as being letters orcharacters, the reflector element 42 may provide any other form of portsor light transmitting regions, such as letters, characters, icons,indicia or the like, without affecting the scope of the presentinvention.

Four individual light emitting diodes (not shown in FIG. 4) may bemounted to the rear of reflector element 42 to individually align withthe port or indicia/icon 46 a, 46 b, 46 c, 46 d so that each LEDindividually emits light through (and thus illuminate) the transparentor at least partially transparent or light transmissive port orindicia/icon 46 a, 46 b, 46 c, 46 d when the particular LED aligned witha particular port or indicia/icon is powered. A photosensor (also notshown in FIG. 4) may be aligned behind transparent/light transmittingregion 48 and may detect ambient light intensity at the interior mirrorassembly. The photosensor may be part of the compass circuitry (notshown) to the rear of reflector element 42. The compass and/or displaycircuitry may be operable to reduce the intensity of light emitted bythe LEDs as the ambient light detected adjacent to mirror assembly 40reduces in intensity so that the display intensity is reduced atdusk/night so as to avoid glaring a driver of the vehicle when in usesuch as during nighttime driving. As shown in FIG. 4, the “N”indicia/icon and the “E” indicia/icon may be illuminated to indicatethat the vehicle is heading in a north-east (NE) direction. Optionally,an additional LED and a corresponding indicia/icon in the silverreflector coating can be provided to assist in calibration and/or zonesetting.

Referring now to FIG. 5, a prismatic interior rearview mirror system orassembly 50 includes a casing or housing 52 and a prismatic reflectiveelement or prism glass 54. The prismatic reflective element 54 includesa reflective surface 54 a on its back surface. The reflective surface 54a may be etched or otherwise modified to remove the reflective surfacecoating in the regions 54 b for the characters or icons associated witha compass system 56 of the present invention. The illumination sources58 or light emitting diodes (LEDs) of compass system 56 may bepositioned on a printed circuit board 60 of mirror assembly 50 andgenerally aligned with the etched regions 54 b to backlight and emitillumination through the etched regions. The printed circuit board 60may be spaced from the reflector element or prism 54 as shown in FIG. 5.

Housing 52 may comprise a polypropylene material or the like and isadjustably mounted to a mirror mount (not shown) positioned at aninterior portion of a vehicle, such as a mirror mounting button on awindshield of the vehicle or any other mounting member at the windshieldor at a headliner or overhead console of the vehicle or the like. Themirror housing may be adjustably mounted at the vehicle via connectionto a single or double ball mounting arrangement, as discussed above withrespect to mirror assembly 10, or via connection to any other mountingarrangement, without affecting the scope of the present invention.Mirror housing 52 may then pivot or actuate around one or more ball andsocket joints or connections to be adjusted relative to the interiorportion of the vehicle to a desired orientation by the driver of thevehicle.

Mirror assembly 50 may include a switch 64 on the printed circuit board60, which may be actuatable to actuate a calibration process of thecompass system 56. Switch 64 may be positioned on printed circuit board60 where it is accessible from outside of the housing, such that a usermay manually actuate switch 64 from outside the housing, such as via apen or other device for actuating switch 64. Optionally, switch 64 maybe actuated via depression of an actuator 62 at housing 52, wherebyinward movement of actuator 62 contacts and actuates switch 64, as canbe seen in FIG. 5. Optionally, the mirror assembly may include a movableor removable cover or plug, which could be moved or removed from theopening in housing 52 to provide access to the switch 64, withoutaffecting the scope of the present invention. Mirror assembly 50 furtherincludes an electrical connector 66 on printed circuit board 60 forconnecting an electrical wire or harness (not shown) to provideelectrical connection from the vehicle to the mirror assembly andcompass system. The wire may extend down from the headliner of thevehicle and through an opening 68 in housing 52 of mirror assembly 50 toconnect to connector 66.

As described above, adjustment of the mirror housing (that includes themirror reflective element) about its pivot connection to its support(typically a double-ball support arm as described above, although asingle-ball support arm can also be used, without affecting the scope ofthe present invention) to the windshield (or to a header region at thejoint of the windshield and the roof of the interior cabin of thevehicle) can cause the compass direction sensing sensor attached to therear of the mirror reflective element to also move. Thus, the compasscontrol circuitry may detect a change in sensed compass directionalsignal (for example, about 3 degrees to about 8 degrees or thereabouts)when the mirror is adjusted by a driver of the vehicle. Should thevehicle be heading in a direction that is close to half-way between oneoctant or another in an 8-octant resolving compass display system, thisadjustment by the driver of the mirror housing to set the rearward fieldof view of the mirror reflective element to suit that driver'sneeds/preference (typically occurring when the driver starts thejourney) may cause the heading displayed to the driver to change from,for example, NW to N because the adjustment by the driver of the mirrorhousing has changed the orientation/alignment of the compass sensor (forexample, a magnetoresistive sensor) relative to the Earth's magneticfield. Modern automatic automotive compass control systems, such asthose described in U.S. Pat. Nos. 4,546,551; 5,699,044; 4,953,305;5,576,687; 5,632,092; 5,644,851; 5,708,410; 5,737,226; 5,802,727;5,878,370; 6,087,953; 6,173,501; and 6,222,460, U.S. patent applicationSer. No. 09/540,702, filed Mar. 31, 2000 by Schierbeek et al. forVEHICLE COMPASS COMPENSATION, now U.S. Pat. No. 6,513,252, and Europeanpatent application, published Oct. 11, 2000 under Publication No. EP 01043566, which are all hereby incorporated herein by reference, compriseprocessing circuitry that includes compensation methods that correct forsuch changes in sensed compass heading. Thus, and as indicated inco-pending U.S. patent application Ser. No. 09/999,429, filed Nov. 15,2001 by DeLine et al. for INTERIOR REARVIEW MIRROR SYSTEM INCORPORATINGA DIRECTIONAL INFORMATION DISPLAY, now U.S. Pat. No. 6,642,851, suchknown compensation methods can be used to recalibrate the compass mirrorsystem of the present invention after adjustment of the mirror housingby the driver.

Techniques and methods for compensating for such adjustments such assuggested in U.S. Pat. No. 6,418,376 (the entire disclosure of which ishereby incorporated herein by reference) may be used in conjunction withthe present invention, but are less desirable as such use a positionsensor (such as a tilt sensor) that determines displacement of themirror housing with respect to a generally horizontal plane, and thuscan add cost to the product. Likewise, the techniques and methodsdescribed in U.S. Pat. Nos. 6,140,933 and 6,023,229, which are herebyincorporated herein by reference, can add cost to the product.

For the low-cost prismatic mirrors of the present invention (note thoughthat many of the aspects or inventions of the present invention mayoptionally be used when an electro-optic reflective element, such as anelectrochromic reflective element, is used), it is preferred not to usethe techniques and methods of those patents cited in the precedingparagraph, but instead it is preferred to use an algorithmic techniquewhereby, when an abrupt change in detected heading is detected that ischaracteristic of an adjustment of the mirror housing by the driver ofthe vehicle, then the automatic compass circuitry changes itscalibration status from its ongoing state (that compensates for suchheading changes over a prolonged period, and one that typically may spanan ignition cycle of the vehicle or several vehicle ignition cycles) toa more aggressive, faster calibration stage that more rapidly, andpreferably within that same ignition cycle, recalibrates the compasssystem and so compensates for the driver's adjustment of the mirrorhousing/casing and for the concomitant movement of the compass sensorhoused therein.

Thus, for example, when a change in compass heading is detected that isindicative of and characteristic of an adjustment of the mirror housingby the driver (such adjustment causes an abnormal change of the compassoutput that is different, such as by magnitude and/or rate of change,than what would occur during normal driving), then the calibrationchanges to a faster compensation algorithm/method. Thus, and referringto U.S. patent application Ser. No. 09/540,702, filed Mar. 31, 2000 bySchierbeek et al, for VEHICLE COMPASS COMPENSATION, now U.S. Pat. No.6,513,252, which is hereby incorporated herein by reference, upondetection of a change in compass heading that is indicative of andcharacteristic of an adjustment of the mirror housing by the driver, thecalibration of the compass system would reinitiate back from Cal-3 (orCal-2) to the beginning of Cal-1. A flow diagram of this is shown inFIG. 6. Note that a mechanical element such as a mechanical movementdetector can be used to detect adjustment by the driver of the mirrorhousing, and the recalibration can be initiated in response to a signaloutput of such a mechanical element.

As shown in FIG. 6, a compass compensation process 70 may provide forinitialization of a rapid calibration stage in response to movement ofthe mirror housing. The compass circuitry may be operable to detect achange in the sensed heading which is characteristic of an adjustment ofthe mirror housing by a driver of the vehicle at 72. The compasscircuitry then responds by reinitializing compass calibration to a rapidcalibration stage at 74. The compass circuitry then compensates for themovement of the compass sensor caused by the adjustment of the mirrorhousing via a microprocessor-based algorithm/software at 76. Aftercompletion of the rapid calibration stage, the compass circuitry mayreturn to its normal operation.

Optionally, the compass circuitry/software can set or return to thebeginning of a rapid calibration stage (such as to the beginning ofCal-1 as described above) each time the mirror compass circuitry isinitially powered, such as by a fresh ignition cycle of the vehicle.Thus, for example, should a driver or occupant of the vehicle adjust theinterior rearview mirror orientation during the immediately previousignition cycle, and thus potentially disturb the established propercompass calibration, then an aggressive and rapid recalibration mayautomatically occur at the start of the following or next ignition cycle(and thus any potential calibration misalignment may only be temporarilyexperienced by the driver).

Also, and optionally, a glare sensor and/or an ambient light sensor andelectrochromic automatic dimming circuitry (such as described incommonly assigned U.S. Pat. Nos. 4,793,690 and 5,193,029, which arehereby incorporated herein by reference) can be included in the compasssystem and/or mirror assembly of the present invention. The ambientlight sensor and glare sensor may be positioned such that the ambientsensor and glare sensor are both facing into the interior cabin of thevehicle. The ambient sensor may be angled and thus sampling light in adirection which is generally different from the glare sensor so itdifferentiates from glare detection. For example, the ambient sensor maybe directed generally upward toward the ceiling of the vehicle, whilethe glare sensor is directed generally rearwardly. The ambient sensorand glare sensor may both be positioned on the printed circuit boardwithin the mirror housing and behind the glass or reflective element andlooking through the glass or reflective element, such as through atransparent window or region, as discussed above.

Referring now to FIGS. 7 and 7A, an interior rearview mirror system 100includes a compass module or pod 110 that is generally fixedly mountedat a mirror mounting arrangement 112 of an interior rearview mirrorassembly 114 of a vehicle. Mirror assembly 114 includes a casing 115 anda reflective element 116 adjustably mounted to the vehicle by the mirrormounting arrangement 112, which may include a mounting arm 112 a and adouble ball or single ball mounting arrangement mounted to a mirrormount 112 b, as is known in the mirror art. Compass module 110 includesa compass sensor 118, a microprocessor 119 and compass control circuitry122, which may include compensation circuitry and the like. Themicroprocessor 119 and compass control circuitry 122 are in electricalcommunication with a display 120 mounted or positioned at the reflectiveelement 116 or casing 115 of the mirror assembly 114. The microprocessor119 and compass control circuitry 122 may be operable to illuminate orenergize one or more illumination sources 124 of display 120 toilluminate a corresponding port or light transmitting region 120 b, suchas a character or letter or icon or the like 120 b at a display area 120a (FIG. 7A) to display a directional heading of the vehicle or otherinformation to a driver of the vehicle, as discussed below.

Mirror casing 115 may be adjustably or pivotally mounted to mirror mount112 b via a double ball or double pivot mirror mounting arrangement,which includes a mounting arm 112 a pivotally mounted at to mirror mount112 b (mounted at the windshield 13 a or headliner 113 b of the vehicle,such as at a mounting button 112 c, which may be adhered or otherwisebonded or secured to the interior surface of the windshield 113 a of thevehicle, such as by using suitable adhesives 112 f or the like) at onepivot joint 112 d and to a mirror casing mount 115 a at another pivotjoint 112 e. An example of a double pivot or double ball mountingarrangement is disclosed in commonly assigned U.S. Pat. Nos. 4,646,210and 6,331,066, which are hereby incorporated herein by reference.Preferably, the mirror mounting components provide a breakaway typeconnection or mount, such as the types disclosed in U.S. Pat. Nos.6,172,613; 6,087,953; 5,820,097; 5,377,949; and/or 5,330,149, which arehereby incorporated herein by reference.

Reflective element 116 may comprise a prismatic reflective element. Theprismatic reflective element 116 may be formed from various materialssuch as plastic or glass, but preferably is glass, and preferably has aplanar front surface 116 a extending at an angle to a planar rearsurface 116 b. Rear surface 116 b is preferably coated with a reflectivelayer of metal such as chromium, aluminum or alloys thereof as isconventionally known in the industry. The mirror casing 115 ispivotable, such as via a toggle or flip mechanism 115 b or the like,relative to mounting arm 112 a and minor mount 112 b to pivot thereflective surface 116 b in order to reduce glare during nighttimeconditions, as is known in the mirror art.

Display 120 provides a display region 120 a, which is preferablypositioned at reflective element 116 (as best shown in FIG. 7A) and isoperable to display a directional heading of the vehicle in response tocompass control circuitry 122, as discussed below. Alternately, however,display 120 may be positioned elsewhere on the mirror assembly, such asat an eyebrow or chin or bezel portion or the like, or elsewhere in thevehicle, without affecting the scope of the present invention.

The display ports or icons or characters or indicia or the like 120 b ofdisplay 120 may include characters or indicia or the like representativeof the cardinal and intercardinal directional points (such as, forexample, the characters N, NE, E, SE, S, SW, W, NW, as shown in FIG. 7A)or may include characters or indicia or the like representative of onlythe cardinal directional points (such as, for example, the characters N,S, E, W, as shown in FIGS. 8A-12A) formed or etched in the reflectivefilm coating of the reflective element 116 (and forming a transparentwindow therein). By etching or demarcating the ports or indiciarepresentative of compass headings into the mirror reflector coating ofthe reflective element, and hence creating a substantially or fullytransparent window therein or therethrough, the reflective elementitself forms part of the display element.

Display region 120 a provides an indication of the directionalinformation on reflective element 116, and is preferably positioned atan upper right hand quadrant of the reflective element (although thedisplay region may be positioned elsewhere on the reflective element orelsewhere on the mirror assembly, without affecting the scope of thepresent invention). The ports or characters or letters 120 b may besandblasted or laser created or chemically etched or otherwise appliedor formed on the rearward surface of the reflective element, such as viatechniques such as disclosed in commonly assigned U.S. Pat. No.4,882,565, issued to Gallmeyer on Nov. 21, 1989, which is herebyincorporated herein by reference. Optionally, however, the display ofthe present invention may be a display on demand type of display, suchas disclosed in commonly assigned U.S. Pat. Nos. 5,668,663 and5,724,187, and U.S. patent application Ser. No. 10/054,633, filed Jan.22, 2002 by Lynam et al. for VEHICULAR LIGHTING SYSTEM, now U.S. Pat.No. 7,195,381; and Ser. No. 09/793,002, filed Feb. 26, 2001, entitledVIDEO MIRROR SYSTEMS INCORPORATING AN ACCESSORY MODULE, now U.S. Pat.No. 6,690,268, the entire disclosures of which are hereby incorporatedby reference herein, without affecting the scope of the presentinvention.

In the illustrated embodiment of FIGS. 7 and 7A, display 120 includeseight illumination sources 124, such as light emitting diodes (LEDs),such as described in U.S. patent application Ser. No. 10/054,633, filedJan. 22, 2002 by Lynam et al. for VEHICULAR LIGHTING SYSTEM, now U.S.Pat. No. 7,195,381, which is hereby incorporated herein by reference, orany other light emitting devices, positioned behind and aligned withrespective or corresponding ones of the ports, such as the eightdirectional characters or points 120 b. Preferably, the illuminationsources or light emitting diodes 124 are positioned on a display blockor printed circuit board 128 mounted at or secured or bonded to the rearsurface of the reflective element 116. Each illumination source 124 ispositioned behind the reflective element and aligned with acorresponding one of the ports or characters 120 b of display 120. Eachindividual illumination source 124 may be energized, either alone or incombination with one or more of the other illumination sources, to emitlight through, and thus provide illumination or back lighting of, therespective transparent or partially transparent or light transmittingport or ports, such as the respective character or characters, indiciaor icons 120 b of display region 120 a, such that the ports orcharacters are backlit by the respective illumination sources, in orderto convey directional information or other information (discussed below)to the driver of the vehicle, in response to energizing or powering of acorresponding wire of cable 126 by microprocessor 119 and/or compasscontrol circuitry 122, as discussed below.

Preferably, illumination sources 124 comprise individual light emittingdiodes. The illumination sources may be high intensity illuminationsources which may be operable in response to a low current input,preferably less than approximately 50 mA, and more preferably less thanapproximately 20 mA. Preferably, the illumination sources are highlyvisible to the driver of the vehicle when they are illuminated, even inhigh ambient lighting conditions, such as in a convertible on a sunnyday. Each illumination source 124 may comprise a blue light emittingdiode, such as an OSRAM LBT673-M2N2-35 light emitting diode or the like,which is particularly visible in such high ambient lighting conditions.However, other color illumination sources may be implemented, such asred, yellow, amber or any other color, without affecting the scope ofthe present invention.

Each illumination source 124 of display 120 is energized in response toa power input from microprocessor 119 via a respective wire 126 a of aconnector cable 126, such that microprocessor 119 activates or energizesor powers a particular wire or wires of the connector cable to activateor energize or power a corresponding illumination source or sources 124of display 120, as discussed below. Preferably, microprocessor 119 hassufficient current handling capability so that the microprocessor candirectly address and power or energize the illumination sources ofdisplay 120. Alternately, the illumination sources 124 may be controlledfrom microprocessor 119 via a single transistor or the like or via arestricted/economical circuit, such as a simple, low cost, low componentcount circuit that ties each of the individual illumination sourcesdirectly to an individual output port/lead/channel of the microprocessor119. The microprocessor 119 thus has direct connection to theillumination sources, which may require between 1 and 5 volts andbetween approximately 10 mA and 50 mA each. Accordingly, themicroprocessor is preferably selected to provide at least four or eightchannels with such power handling capability, depending on the number ofillumination sources provided at the display, as discussed below.

Compass module 110 may be generally fixedly mounted to mirror mount 112b, such as by utilizing the principles disclosed in U.S. Pat. Nos.5,708,410 and/or 5,576,687, which are hereby incorporated herein byreference. Compass module 110 may include a printed circuit board (PCB)130 which is mounted or positioned within a housing 110 a of module 110,such as generally horizontally within housing 110 a, as shown in FIG. 7.The microprocessor 119 and all of the compass control circuitry 122,including the compass compensation circuitry/software and the like, andcompass sensor 118 may be positioned on printed circuit board 130.Because compass module 110 may be generally fixedly mounted to mirrormount 112 b, the housing 110 a, circuit board 130 and the associatedcompass sensors 118, microprocessor 119 and compass control circuitry122 thus may be generally fixedly mounted relative to the mirror mount112 b, and thus relative to the vehicle. Accordingly, additionalcompensation circuitry or algorithms or devices for approximating orcanceling any adjustment or repositioning of the compass sensors andcircuitry are not necessary.

Microprocessor 119 and/or compass circuitry 122 are in electricalcommunication with each illumination source 124 of display 120 via cable126, which comprises multiple individual wires 126 a connected betweenthe printed circuit board 130 of compass module 110 and the illuminationsources 124 of display 120 (or the display block or circuit board 128 ofreflective element 116). The cable 126 may be conduited along andthrough the support arm 112 a and into casing 115 or may otherwise berouted from compass module 110 to mirror casing 115, without affectingthe scope of the present invention.

In the illustrated embodiment of FIGS. 7 and 7A, cable 126 comprisesnine individual wires 126 a, with one wire connecting between aparticular output of microprocessor 119 and a corresponding particularillumination source 124 of display 120. Eight of the wires 126 a thusmay individually provide power to a respective illumination source 124,such that when one of the wires 126 a is energized by microprocessor119, the corresponding illumination source 124 will be energized oractuated to illuminate the appropriate corresponding port or character120 b of display 120. The ninth wire of cable 126 may be provided as areturn or ground wire from display 120 or display block or circuit board128 to circuit board 130 of compass module 110. The cable 126 may beconnected to circuit board 130, such as via a plug connector 132 a and acorresponding socket connector 132 b, such as at casing or housing 110 aof compass module 110, to ease assembly and connection of the compassmodule 110 to the mirror mount 112 b and to the display 120, asdiscussed below. An appropriate opening (not shown) may be formed incasing 115 of mirror assembly 114 for cable 126 to pass therethrough toconnect to display 120 and compass module 110, as can be seen in FIG. 7.

Because compass module 110 is suitable for implementation with a lowcost mirror assembly, which may not contain or include electricalcomponents and circuitry, a wire harness or cable 134 may be provided toconnect compass module 110 to the vehicle battery and/or ignition. Thewire harness 134 may extend down from the headliner 113 b of the vehicleand connect to compass module 110 and circuit board 130, such as via aplug connector 136 a and a corresponding socket connector 136 b (asshown in FIG. 7) or the like. Wire harness 134 provides power to circuitboard 130, and may provide power only when the ignition of the vehicleis on. Optionally, the wire harness 134 may provide power and/or controlto other accessories or devices (such as the accessories discussedbelow) positioned at, near or within the compass module 110 and/or themirror assembly 114, without affecting the scope of the presentinvention.

The compass sensor 118 of compass module 110 functions to detect adirectional heading of the vehicle relative to the earth's magneticfield, as is known in the art. Compass sensor 118 may be any knownsensor type, such as a magnetoresponsive sensor, such as amagnetoresistive sensor (such as described in U.S. Pat. Nos. 6,427,349;5,802,727; and 5,255,442, and U.S. patent application Ser. No.09/540,702, filed Mar. 31, 2000 by Schierbeek et al. for VEHICLE COMPASSCOMPENSATION, now U.S. Pat. No. 6,513,252, which are hereby incorporatedherein by reference), a magnetocapacitive sensor, a magnetoinductivesensor, or a flux-gate sensor or the like, without affecting the scopeof the present invention. The compass sensor may include a pair ofmagnetoresponsive sensors positioned generally orthogonal to oneanother. The pair of generally orthogonal sensors are preferablyoriented relative to the vehicle such that one of the sensors isgenerally parallel to the floor of the vehicle and pointing generallyforwardly in the direction of travel of the vehicle, while the other isgenerally orthogonal or perpendicular to the first sensor.

The compass sensor or sensors 118 may provide an output signal tocompass processing circuitry 122, which may be operable to process theoutput signal to determine the vehicle heading and to actuate or controlor adjust an output of display 120 via microprocessor 119 in response tothe output signal of sensor 118. Such processing circuitry may includevarious compensation methods, such as described in U.S. Pat. Nos.4,546,551; 5,699,044; 4,953,305; 5,576,687; 5,632,092; 5,644,851;5,708,410; 5,737,226; 5,802,727; 5,878,370; 6,087,953; 6,173,501; and6,222,460, and U.S. patent application Ser. No. 09/999,429, filed Nov.15, 2001 by DeLine et al. for INTERIOR REARVIEW MIRROR SYSTEMINCORPORATING A DIRECTIONAL INFORMATION DISPLAY, now U.S. Pat. No.6,642,851, and European patent application, published Oct. 11, 2000under Publication No. EP 0 1043566, which are all hereby incorporatedherein by reference.

Microprocessor 119 and compass control circuitry 122 may be operable toenergize or power (or make hot) one of the wires 126 a of cable 126, inorder to provide power to an appropriate, corresponding illuminationsource 124 of display 120, such that the appropriate illumination sourcemay be illuminated, and thus the appropriate port or icon or characteror indicia 120 b may be illuminated, to indicate the directional headingof the vehicle at display 120. Accordingly, each illumination source 124of display 120 may be independently actuated or energized via electricalpower provided by a respective wire of the connector cable in responseto microprocessor 119.

In applications where the display may include only the four cardinalpoint characters N, S, E, W (or icons or indicia or the likerepresentative of the four cardinal directional points), such as shownin FIGS. 8-12 discussed below, then the compass control circuitry andmicroprocessor may be operable to individually or simultaneouslyenergize one or two wires of the cable (which may be a four or five wirecable) to illuminate an appropriate one or two characters, withoutaffecting the scope of the present invention. For example, if thedirectional heading is generally north, then the single wire to theillumination source behind the N character may be powered, while if thedirectional heading is generally northeast, then the wires to both ofthe illumination sources behind the N and the E may be powered.

Microprocessor 119 and compass control circuitry 122 thus includeprocessing circuitry which may be operable to actuate or energize one ormore of the illumination sources 124 in response to an output from thecompass sensor or sensors 118. For example, the illumination sourcebehind the letter N may be energized or actuated when the vehicle isheading generally Northward and within a particular range of Northward.As discussed above with respect to mirror assembly 10, each respectiveone of the illumination sources may be illuminated when the vehicle iswithin a predetermined range of the particular direction at therespective cardinal point (N, S, E, W) or inter-cardinal point (NE, SE,SW, NW).

Compass module 110 and circuit board 130 may also include a calibrationbutton or switch 138 and a zone button or switch 140 for manuallytriggering a calibration mode and zone setting mode, respectively, ofthe compass circuitry 122. An access hole or holes 138 a and 140 a foraccessing calibration button 138 and zone button 140 or other button orbuttons or the like (such as for initiating calibration of the compasssystem if needed or to set a zone of the compass system as needed, as isknown in the compass art), may be provided in housing 110 a for manualaccess of the buttons or switches associated with compass circuitry 122or compass module 110. Correspondingly, the owner or driver of thevehicle may access one or more user control buttons (such as for manualactuation of a compass calibration mode or the like) through openings inthe compass module casing, such as with their finger, a pen or otherinstrument or the like. Preferably, any such openings are provided onthe casing for accessing connectors and buttons and the like on theprinted circuit board within the compass module casing.

Circuit board 130 may also include a photo detector or sensor 142, suchas a photo transistor, a photo resistor, a photo diode or the like,which may be operable to sense the ambient light intensity levelssurrounding the mirror assembly or the light from headlights of vehiclesrearward of the subject vehicle. The photosensor 142 preferably ispositioned or mounted on the printed circuit board 130 and may bepositioned, aligned and directed to receive illumination through anaperture or hole 142 a in the housing 110 a of compass module 110. Thephotosensor 142 is operable to detect the ambient light levels generallysurrounding the compass module 110 and the mirror assembly 114 in orderto provide for dimming of the output of illumination sources 124 ofdisplay 120 in darkened lighting conditions, such as at nighttimeconditions, in order to reduce the intensity of display 120 to reduceglare and distraction and annoyance to the driver of the vehicle. Thephotosensor 142 may comprise a silicon photosensor, such as a TSL235RLight-to-Frequency converter (available from Texas AdvancedOptoelectronic Solutions Inc. of Piano, Tex.). Such light-to-frequencyconverters comprise the combination of a silicon photodiode and acurrent-to-frequency converter on a single monolithic CMOS integratedcircuit. Such light-to-frequency converters have the advantage of beingoperable to directly provide input to the microprocessor 119, thussimplifying circuitry and reducing costs. Alternately, light-to-digitaloutput (such as pulse width modulation or serial output) photosensorscan be used, such as are known in the art. As described above andhereunder, microprocessor 119 may receive inputs directly from whatevertransducers are involved, such as from a light-to-frequency converter,compass sensor or sensors, user input switches and/or the like, and,having processed the inputs to provide a compensated compass headingcorrected for the geographic zone involved, may directly power theillumination sources of the display. Further, the microprocessor may beoperable to perform other functions as well, without affecting the scopeof the present invention.

Photosensor 142 may provide an output signal directly to microprocessor119, such as via a frequency input or pulse-width modulated signal, orserial digital signal or other digital signal or the like.Microprocessor 119 and control circuitry 122 thus may be operable inresponse to photosensor 142 to reduce the intensity of light emitted bythe illumination sources or light emitting diodes 124 as the ambientlight detected adjacent to compass module 110 reduces in intensity sothat the display intensity is reduced at dusk/night so as to limit orreduce or avoid glaring a driver of the vehicle when in use such asduring nighttime driving. Optionally, such dimming of the display 120may be performed in response to an instrument panel dimming system ofthe vehicle, without affecting the scope of the present invention. Theprinted circuit board 130 may include other electronic components, suchas integrated circuits, resistors, capacitors, diodes and/or the like.

Optionally, and preferably, when a near infrared sensitive photosensor,such as the silicon photodiode described above, is utilized, a nearinfrared absorbing filter may be disposed in front of the photosensor toreduce the intensity of near infrared/infrared radiation incident on thephotosensor detector surface, and thus reduce the intensity of solarnear infrared radiation and/or headlamp near infrared radiation incidenton the photosensor detector surface. In this regard, it is preferredthat a lens, such as an optical lens or the like, that includes aninfrared filter be utilized, such as can be economically achieved byadding near infrared/infrared absorbing compounds (such as disclosed inU.S. Pat. Nos. 6,117,370; 5,959,105 and 5,024,923, which are herebyincorporated herein by reference) into an optical lens material, such asan acrylic or polycarbonate or polystyrene or the like. More preferably,the near infrared/infrared filtering compound may be added to orcompounded with the transparent optical lens material during aninjection molding operation (i.e., the near infrared/infrared filteringcompound and the optical molding resin are mixed together, injected intothe molding tool cavity, and thus formed into the substantially visiblelight transmitting, reduced near infrared/infrared transmitting, opticallens/filter). For example, a filter, lens, light pipe, light conduit orthe like can be formed from an optical molding resin (such as acrylic,polycarbonate, CR39, cyclic olefin copolymer, polystyrene or the like)that may include a near infrared absorbing dihydroperimidine squaryliumcompound or the like, or can be, for example, formed of an acrylic orsimilar optical resin material containing a phosphoric acid-groupcontaining a metal ion (such as, for example, a bivalent copper ion orthe like). Alternately, a diammonium compound can be used or adithiol-nickel complex can be used. Alternately, a glass filterutilizing a phosphate glass can be used or near infrared/infraredabsorbing filters can be used, such as described in U.S. Pat. No.4,799,768, which is hereby incorporated herein by reference. Also, andoptionally, the near infrared filter can be integrally molded with orotherwise established with the photosensor device so that thephotosensor device can be obtained from a photosensor supplier with theinfrared filter absorbing compound incorporated into/compounded into thelens cover provided with the photosensor device. Or, alternatively, aseparate and distinct near infrared filtering lens or light conduit orlight pipe (formed by molding as described above to include nearinfrared absorbing material) can be provided as a separate part from thephotosensor device.

Optionally, as discussed above with respect to the processing circuitryof mirror assembly 10, compass control or microprocessor 119 andprocessing circuitry 122 may also be operable to activate one or more ofthe illumination sources 124 to convey other information to the driverof the vehicle via display 124. For example, if the compass system is ina calibration mode, one or more, or all four or eight, of theillumination sources may be illuminated or may be flashed until thecalibration of the compass system is complete (clearly, othercombinations of illumination may be implemented, without affecting thescope of the present invention). Also, the microprocessor 119 may beoperable to convey information pertaining to the calibration mode orzone setting mode for a particular zone in which the vehicle is locatedvia display 120, in a similar manner as discussed above. Optionally, asalso discussed above, display 120 may include an additional indicator orindicators (not shown), such that when the additional indicator isilluminated or energized by microprocessor 119, the meaning of or theinformation conveyed by the combination of display characters beingilluminated changes to a second set of meanings, in order to double theamount of information that may be conveyed by the display 120. It isenvisioned that other information may be conveyed via display 120 andoptionally one or more additional indicators may be provided, withoutaffecting the scope of the present invention.

Because microprocessor 119 and control circuitry 122 are operable toprovide electrical power to one or more illumination sources of thedisplay, no encoding or decoding of the signal is required at display120 to provide a correct display output in response to the signal fromcompass control circuitry 122 and microprocessor 119. The presentinvention thus obviates the need for such costly processing and thusprovides a low cost compass module and display system for providingdirectional information to a driver of a vehicle. Additionally, becausethe circuitry and microprocessor and circuit board are within the moduleor pod which is remote from the mirror assembly, the mirror assembly maycomprise a lighter mirror assembly, which may result in reducedvibration over conventional compassized mirror assemblies.

Referring now to FIGS. 8 and 8A, an interior rearview mirror system 200includes a compass pod or module 210 that is generally fixedly mountedat a mirror mount 212 b of a prismatic interior rearview mirror assembly214 of a vehicle. Mirror assembly 214 includes a casing 215 and aprismatic reflective element 216 adjustably mounted to mirror mount 212b, such as via a mounting arm 212 a and a double ball or single ballmounting arrangement, as is known in the mirror art. Compass module 210includes a compass sensor 218, a microprocessor 219 and compass controlcircuitry 222, which includes compensation circuitry and the like,similar to compass module 110 discussed above. The microprocessor 219and compass control circuitry 222 are in electrical communication with adisplay 220 mounted or positioned at the reflective element 216 orcasing 215 of the mirror assembly 214, and are operable to illuminate orenergize one or more illumination sources 224 of display 220 toilluminate a corresponding light transmitting port 220 b, which maycomprise a character or letter or icon or the like, to display adirectional heading of the vehicle to a driver of the vehicle. Eachillumination source 224 of display 220 may be energized in response to apower input from microprocessor 219 via a respective wire 226 a of aconnector cable 226, such that microprocessor 219 may activate orenergize or power a particular wire or wires of the connector cable toactivate or energize or power a corresponding illumination source orsources 224 of display 220, as discussed above.

Mirror assembly 214 and compass module 210 of mirror system 200 aresubstantially similar to mirror assembly 114 and compass module 110 ofmirror system 100 discussed above, such that a detailed discussion ofthe mirror assembly and compass module will not be repeated herein. Thecommon components of the compass modules and mirror assemblies are shownin FIGS. 8 and 8A with the reference numbers of mirror assembly 114 andcompass module 110 having 100 added thereto.

Display 220 provides a display region 220 a operable to display adirectional heading of the vehicle in response to microprocessor 219 andcompass control circuitry 222. Display 220 includes a plurality ofillumination sources 224, such as light emitting diodes and such as bluelight emitting diodes, such as an OSRAM LBT673-M2N2-35 light emittingdiode or the like, operable to illuminate one or more ports or regionsor appropriate characters or letters 220 b (FIG. 8A) to indicate thedirection in which the vehicle is driving. The display ports orcharacters 220 b of display 220 include only the four cardinaldirectional points (such as, for example, the characters N, S, E, W)formed or etched in the reflective film coating of the reflectiveelement 216 (and forming a transparent window therein).

Display 220 may include a calibration indicator or illumination source225, such as a light emitting diode, and preferably a red, yellow oramber light emitting diode, and a corresponding calibration indicatorview port 220 c at display area 220 a, such that light emitted fromindicator 225 is viewable through view port 220 c at reflective element216. Display 220 may also include an ambient light photosensor 242 forsensing ambient light at the reflective element 216, while display area220 a includes a photosensor port 220 d, such as at a central region ofthe compass display, through which photosensor 242 receives lightsurrounding reflective element 216.

Microprocessor 219 and compass circuitry 222 on printed circuit board230 within compass module 210 are in electrical communication with eachillumination source 224, 225 and photosensor 242 of display 220 viacable 226, which preferably comprises a multiwire cable having multipleindividual wires 226 a connected between the printed circuit board 230and the illumination sources 224, 225 and photosensor 242 (or thedisplay block or circuit board 228 of reflective element 216). In theillustrated embodiment of FIGS. 8 and 8A, cable 226 comprises sevenindividual wires 226 a, with one wire connecting between a particularoutput of microprocessor 219 and a corresponding particular illuminationsource 224, calibration indicator 225 or photosensor 242. Four of thewires 226 a thus may individually provide power to a respectiveillumination source 224, such that when one of the wires 226 a isenergized by microprocessor 219, the corresponding illumination source224 will be energized or actuated to illuminate the appropriatecorresponding character 224 b of display 220. Likewise, if two wires 226a are energized or made hot, two illumination sources 224 may beenergized, such as the illumination sources behind the N and Echaracters of display 220, so as to indicate to the driver of thevehicle that the vehicle is heading in a northeasterly direction.Another wire 226 a may connect between microprocessor 219 andcalibration indicator 225, such that indicator 225 may be energized in asimilar manner as discussed above. The remaining two wires 226 a ofcable 226 are connected between microprocessor 219 and photosensor 242to provide an output of photosensor 242 to microprocessor 219.

Each illumination source 224 may be energized, either alone or incombination with one or more of the other illumination sources, toprovide illumination of or through the respective port or ports (orletter or letters) 220 b of display region 220 a, such that the ports orcharacters are backlit or illuminated by the respective illuminationsources, in order to convey directional information or other informationto the driver of the vehicle, in response to energizing or powering of acorresponding wire of cable 226 by microprocessor 219 and/or compasscontrol circuitry 222. Indicator 225 likewise may be energized toprovide illumination through view port 220 c to indicate to the driverof the vehicle that the compass circuitry is operating in itscalibration mode. Microprocessor 219 and/or compass circuitry 222 may beoperable to adjust the intensity of the illumination sources 224 andindicator 225 in response to photosensor 242.

Referring now to FIGS. 9 and 9A, an interior rearview mirror system 300includes a compass pod or module 310 that is generally fixedly mountedat a mirror mount 312 b of an electro-optic interior rearview mirrorassembly 314 of a vehicle. Mirror assembly 314 includes a casing 315 andan electro-optic reflective element 316 adjustably mounted to mirrormount 312 b (which may be mounted to or at the windshield 313 a, such asat a mounting button 312 c adhered or bonded or otherwise affixed to thewindshield, or headliner 313 b of the vehicle), such as via a mountingarm 312 a and a double ball or single ball mounting arrangement, as isknown in the mirror art. Compass module 310 includes a compass sensor318, a microprocessor 319 and control circuitry 322, which includes thecompass, and display control circuitry and compass compensationcircuitry and the like, similar to compass module 110 discussed above.Control circuitry 322 may also include electro-optic reflective elementautomatic dimming or powering circuitry, and microprocessor 319 may befurther operable to control the electro-optic reflective element 316 viaflowing electricity across reflective element 316 to darken theelectrochromic medium as desired or in response to photosensors 343,342, discussed below.

Advantageously, the microprocessor of the present invention thus mayperform multiple functions, such as receive inputs from a compass sensorand/or temperature sensor or the like, and process the input andgenerate an appropriate output signal. Optionally, the microprocessormay control an electro-optic dimming device, and may do so in responseto an input from one or more photosensors or the like.

Mirror assembly 314 and compass module 310 of mirror system 300 aresubstantially similar to mirror assembly 114 and compass module 110 ofmirror system 100 discussed above, such that a detailed discussion ofthe mirror assembly and compass module will not be repeated herein. Themicroprocessor 319 and compass control circuitry 322 are in electricalcommunication with a display 320 mounted or positioned at the reflectiveelement 316 or casing 315 of the mirror assembly 314, and are operableto illuminate or energize one or more illumination sources 324 ofdisplay 320 to illuminate a corresponding port or region or character,letter, icon or indicia 320 b of a display region 320 a to display adirectional heading of the vehicle to a driver of the vehicle. Eachillumination source 324 of display 320 may be energized in response to apower input from microprocessor 319 and/or compass control circuitry 322via a respective wire 326 a of a connector cable 326, such thatmicroprocessor 319 may activate or energize or power a particular wireor wires of the connector cable to activate or energize or power acorresponding illumination source or sources 324 of display 320, asdiscussed above.

Display 320 includes a calibration indicator or illumination source 325and a corresponding calibration indicator view port 320 c at displayarea 320 a, such that light emitted from indicator 325 is viewablethrough view port 320 c at reflective element 316. Display 320 alsoincludes a glare detecting photosensor 343 for sensing or detectingheadlamps of a vehicle that is approaching the subject vehicle from therear, while display area 320 a includes a photosensor port 320 d, suchas at a central region of the compass display, through which photosensor343 receives light surrounding reflective element 316.

In the illustrated embodiment of FIGS. 9 and 9A, cable 326 comprisesnine individual wires 326 a, with one wire connecting between aparticular output of microprocessor 319 and a corresponding particularillumination source 324, calibration indicator 325 or photosensor 343.Four of the wires 326 a thus may individually or in combination providepower to one or more respective illumination sources 324, as discussedabove. Another wire 326 a may connect between microprocessor 319 andcalibration indicator 325, such that indicator 325 may be energized in asimilar manner as discussed above. Also, two wires 326 a of cable 326are connected between microprocessor 319 and photosensor 343 to providean output of photosensor 343 to compass circuitry 322. The remaining twowires 326 a may be connected to the connectors or bus bars (not shown)of the electro-optic reflective element 316 to provide a flow ofelectricity across reflective element 316 to darken the electrochromicmedium as desired or in response to photosensors 343, 342.

Microprocessor 319 and control circuitry 322 include the electro-opticreflective element automatic dimming powering circuitry, and are thusoperable to control or automatically dim or darken the electro-opticelement 316 in response to the glare detecting photosensor 343 atreflective element 316 and/or the ambient light photosensor 342 atcompass module 310. Microprocessor 319 and control circuitry 322 mayalso be operable to adjust the intensity of the illumination sources 324and indicator 325 in response to glare detecting photosensor 343 and/oran ambient light photosensor 342. The photosensor 342 and/or 343 maythus be operable in conjunction with the electro-optic reflectiveelement automatic dimming circuitry and with the night time dimming ofthe illumination sources 324 and/or 325. Preferably, microprocessor 319has sufficient current handling capability to directly address theillumination sources 324, 325 of display 320. However, the illuminationsources may be controlled by microprocessor 319 via a single transistoror the like, without affecting the scope of the preset invention.

Photosensors 342, 343 may directly feed to microprocessor 319, such asvia a frequency input or a pulse width modulated signal, or a serialdigital signal or other digital signal or the like. The glare detectingphotosensor 342 may comprise a rearward viewing glare detector orsensor, while photosensor 342 may comprise a forward viewing and/orsideward viewing ambient light detector or sensor, such as described inU.S. Pat. No. 4,793,690, which is hereby incorporated herein byreference. Optionally, photosensors 342, 343 may comprise a siliconphotosensor, such as a TSL235R Light-to-Frequency converter (availablefrom Texas Advanced Optoelectronic Solutions Inc. of Plano, Tex.). Suchlight-to-frequency converters comprise the combination of a siliconphotodiode and a current-to-frequency converter on a single monolithicCMOS integrated circuit. Optionally, the microprocessor of compassmodule 310 may be operable in response to a single photosensor, such asdescribed in U.S. Pat. No. 5,193,029, which is hereby incorporatedherein by reference, without affecting the scope of the presentinvention.

Similar to compass module 110, cable 326 of compass module 310 may beconnected to circuit board 330 via a plug connector 332 a and acorresponding socket connector 332 b or the like to ease assembly andconnection of the compass module 310 to the mirror mount 312 b and tothe display 320, as discussed below. Likewise, similar to compass module310, a wire harness or cable 334 may be provided to connect compassmodule 310 to the vehicle battery and/or ignition. The wire harness 334may extend down from the headliner 313 b of the vehicle and connect tocompass module 310 and circuit board 330 via a plug connector 336 a anda corresponding socket connector 336 b or the like. Wire harness 334provides power to circuit board 330, and may provide power only when theignition of the vehicle is on. Optionally, the wire harness 334 mayprovide power and/or control to other accessories or devices (such asthe accessories discussed below) positioned at, near or within thecompass module 310 and/or the mirror assembly 314, without affecting thescope of the present invention. Also similar to compass module 110,discussed above, compass module 310 and circuit board 330 may alsoinclude a calibration button or switch 338 and a zone button or switch340 for manually triggering a calibration mode or a zone setting mode orresetting the compass circuitry 322.

Because the microprocessor 319 and control circuitry 322 are operable toprovide electrical power to one or more illumination sources of thecompass display, no encoding or decoding of the signal is required toprovide a correct compass display output in response to the signal frommicroprocessor 319. The present invention thus obviates the need forsuch costly processing and thus provides a low cost compass module anddisplay system for providing directional information to a driver of avehicle. Also, because microprocessor 319 provides the controls for anelectro-optic reflective element, no such circuitry is required withinthe mirror case 315, such that a low cost prismatic interior rearviewmirror assembly may be converted to an electro-optic mirror assembly byproviding an electro-optic or electrochromic reflective element withinthe casing.

The compass and electrochromic circuitry module 310 may thus beincorporated at or near or with a mirror assembly which may not includethe electrochromic circuitry (such as a mirror assembly designed to be aprismatic mirror assembly). An electrochromic reflective element may besnapped into or otherwise mounted or installed to the mirror assembly,in order to transform the mirror assembly into an electro-optic orelectrochromic mirror assembly with a compass display. Themicroprocessor of compass module 310 may then control the electrochromicreflective element via the multiwire cable connection. The output of themicroprocessor may also control an outside electrochromic mirror as wellas the interior rearview electrochromic mirror, without affecting thescope of the present invention.

Referring now to FIGS. 10 and 10A, an interior rearview mirror system300′ includes a compass pod or module 310′ that is generally fixedlymounted at a mirror mount 312 b of an electro-optic interior rearviewmirror assembly 314′ of a vehicle. Mirror assembly 314′ and compassmodule 310′ of mirror system 300′ are substantially similar to mirrorassembly 314 and compass module 310 of mirror system 300 discussedabove, such that a detailed discussion of the mirror assembly andcompass module will not be repeated herein. The common components of themirror systems are shown in FIGS. 10 and 10A with the same referencenumbers as assigned to the respective components in FIGS. 9 and 9A.Compass module 310′ includes a glare detecting photosensor 343′ forsensing ambient light at the compass module. Microprocessor 319, compasscircuitry 322 and photosensor 343′ are positioned on circuit board 330within compass module 310′.

Display 320′ provides a display region 320 a′ operable to display adirectional heading of the vehicle in response to microprocessor 319 andcompass control circuitry 322. Display 320′ includes a plurality ofillumination sources 324 operable to illuminate one or more appropriateports or light transmitting regions 320 b, which may define characters,letters, icons or other indicia or the like, to indicate the directionin which the vehicle is driving. Display 320′ also includes acalibration indicator or illumination source 325 and a correspondingcalibration indicator view port 320 c at display area 320 a, such thatlight emitted from indicator 325 is viewable through view port 320 c atreflective element 316.

In the illustrated embodiment of FIGS. 10 and 10A, cable 326′ compriseseight individual wires 326 a, with one wire connecting between aparticular output of microprocessor 319 and a corresponding particularillumination source 324 and calibration indicator 325. Four of the wires326 a thus may individually or in combination provide power to one ormore respective illumination sources 324, as discussed above. Anotherwire 326 a may connect between microprocessor 319 and calibrationindicator 325, such that indicator 325 may be energized in a similarmanner as discussed above. Another wire may then act as a return orground wire from the illumination sources to the circuit board 330′. Theremaining two wires 326 a may be connected to the connectors or bus bars(not shown) of the electro-optic reflective element 316 to provide aflow of electricity across reflective element 316 to darken theelectrochromic medium as desired or in response to photosensors 343′,342.

Similar to compass module 310, discussed above, microprocessor 319 ofcompass module 310′ may be operable to control or energize theillumination sources 324, 325 via cable 326′ in response to controlcircuitry 322, Microprocessor 319 may be further operable to adjust theintensity of illumination sources 324, 325 in response to photosensor342. Also, microprocessor 319 may be operable to control or adjust thedimming or darkening of electro-optic reflective element 316 in responseto glare detecting photosensor 343′ and ambient sensing photosensor 342.The photosensors 342 and/or 343′ may thus be operable in conjunctionwith the electro-optic reflective element automatic dimming circuitryand with the night time dimming of the illumination sources 324 and/or325.

Referring now to FIGS. 11 and 11A, an interior rearview mirror system300″ includes a compass pod or module 310″ that is generally fixedlymounted at a mirror mount 312 b of an electro-optic interior rearviewmirror assembly 314″ of a vehicle. Mirror assembly 314″ and compassmodule 310″ of mirror system 300″ are substantially similar to mirrorassembly 314 and compass module 310 of mirror system 300 discussedabove, such that a detailed discussion of the mirror assembly andcompass module will not be repeated herein. The common components of themirror systems are shown in FIGS. 11 and 11A with the same referencenumbers as assigned to the respective components in FIGS. 9 and 9A.

A display 320″ provides a display region 320 a″ operable to display adirectional heading of the vehicle in response to compass controlcircuitry 322. Display 320″ includes a plurality of illumination sources324 operable to illuminate one or more appropriate ports or lighttransmitting regions 320 b, which may define characters, letters, icons,indicia or the like, to indicate the direction in which the vehicle isdriving. Display 320″ also includes a calibration indicator orillumination source 325, such as a light emitting diode, and preferablya red, yellow or amber light emitting diode, and a correspondingcalibration indicator view port 320 c at display area 320 a, such thatlight emitted from indicator 325 is viewable through view port 320 c atreflective element 316.

Display 320″ further includes a temperature display 323, such as at agenerally central region of display area 320 a″. Microprocessor 319″ isoperable to receive an input from a temperature sensor (not shown),which may be positioned within the vehicle (such as within the compassmodule) to provide an interior temperature reading or outside of thevehicle cabin to provide an exterior temperature reading. Compass module310″ and microprocessor 319″ are operable to control temperature display323 to display an interior or exterior temperature to the driver of thevehicle at display area 320 a″ in response to the temperature sensor.The compass module 310″ of mirror system 300″ thus provides a low costtemperature display to an interior rearview mirror assembly of avehicle. Although shown and described as comprising a temperaturedisplay 323, it is envisioned that other display information,characters, indicia or other accessories may be provided at the display,such as discussed below, without affecting the scope of the presentinvention.

Temperature display 323 may comprise one of many types of displays, suchas a vacuum fluorescent (VF) display, a light emitting diode (LED)display, an organic light emitting diode (OLED) display, a liquidcrystal display (LCD), an electro-luminescent (EL) display, a videoscreen display or the like. Optionally, however, the temperature displaymay comprise a display on demand type of display, such as disclosed incommonly assigned U.S. Pat. Nos. 5,668,663 and 5,724,187, and U.S.patent application Ser. No. 10/054,633, filed Jan. 22, 2002 by Lynam etal. for VEHICULAR LIGHTING SYSTEM, now U.S. Pat. No. 7,195,381; and Ser.No. 09/793,002, filed Feb. 26, 2001, entitled VIDEO MIRROR SYSTEMSINCORPORATING AN ACCESSORY MODULE, now U.S. Pat. No. 6,690,268, theentire disclosures of which are hereby incorporated by reference herein,without affecting the scope of the present invention. For economy, aliquid crystal display may be preferred.

Similar to compass module 310′, compass module 310″ includes a glaredetecting photosensor 343′ for sensing ambient light at the compassmodule. Microprocessor 319″ and compass circuitry 322 are mounted to orpositioned on a printed circuit board 330″ and are in electricalcommunication with photosensor 343′ and may also be operable to adjustthe intensity of illumination sources 324, 325 and/or to adjust thedimming or darkening of electro-optic reflective element 316 in responseto glare detecting photosensor 343′ and ambient sensing photosensor 342.The photosensor 342 and/or 343′ may thus be operable in conjunction withthe electro-optic reflective element automatic dimming circuitry andwith the night time dimming of the illumination sources 324 and/or 325.

In the illustrated embodiment of FIGS. 11 and 11A, cable 326″ comprisesnine individual wires 326 a, with one wire connecting between aparticular output of microprocessor 319″ and a corresponding particularillumination source 324 and calibration indicator 325. Four of the wires326 a thus may individually or in combination provide power to one ormore respective illumination sources 324, while a fifth wire 326 aconnects between microprocessor 319″ and calibration indicator 325, asdiscussed above. Two wires 326 a may connect between microprocessor 319″and temperature display 323. The remaining two wires 326 a may beconnected to the connectors or bus bars (not shown) of the electro-opticreflective element 316 to provide a flow of electricity acrossreflective element 316 to darken the electrochromic medium as desired orin response to photosensors 343′, 342.

Referring now to FIGS. 12 and 12A, an interior rearview mirror system400 includes a compass pod or module 410 that is generally fixedlymounted at a mirror mount 412 b of an electro-optic interior rearviewmirror assembly 414 of a vehicle, Mirror assembly 414 includes a casing415 and an electro-optic reflective element 416 adjustably mounted tomirror mount 412 b, such as via a mounting arm 412 a and a double ballor single ball mounting arrangement, as is known in the mirror art.Compass module 410 includes a compass sensor 418, a microprocessor 419and compass control circuitry 422, which includes compensation circuitryand the like, similar to compass module 310 discussed above.Microprocessor 419 and compass control circuitry 422 may be operable tocontrol a display 420 at reflective element 416 via wires 426 a, and maydim or adjust the intensity of the illumination sources 424, 425 ofdisplay 420, and may dim or adjust dimming or darkening of electro-opticreflective element 416 in response to glare detecting photosensor 443and ambient sensing photosensor 442, such as in the manner describedabove. Mirror assembly 414 and compass module 410 of mirror system 400are substantially similar to mirror assembly 314 and compass module 310of mirror system 300 discussed above and as shown in FIGS. 9 and 9A,such that a detailed discussion of the mirror assembly and compassmodule will not be repeated herein. The common components of the compassmodules and mirror assemblies and mirror systems are shown in FIGS. 12and 12A with the reference numbers of mirror assembly 314 and compassmodule 410 of mirror system 300 having 100 added thereto.

Compass module 410 includes a temperature display 423 positioned atmodule housing 410 a to display a measured temperature to the driver ofthe vehicle. In the illustrated embodiment, temperature display 423 ispositioned at a lower portion or extension 410 b of module 410 and ispositioned so as to be viewable beneath the mirror assembly 414 by adriver of the vehicle, as can be seen in FIG. 12A. By positioning thetemperature display 423 in the compass module 410, compass module 410may provide an additional display, while the display 420 at reflectiveelement 416 may include glare detecting photosensor 443, withoutrequiring additional wiring to the mirror casing or controls within themirror casing. Although shown and described as comprising a temperaturedisplay 423, it is envisioned that the compass module of the presentinvention may provide other auxiliary or additional display or displays,such as a tire pressure display, a passenger side inflatable restraint(PSIR) status display, a time display or clock, a seat belt statusdisplay, a door status display, an accessory status display, or otheraccessory status or the like or other display information, characters,indicia or the like, or other accessories or the like or an illuminationsource or light source at the compass module, such as discussed below,without affecting the scope of the present invention.

Microprocessor 419 is operable to receive an input from a temperaturesensor (not shown), which may be positioned within the vehicle (such aswithin the compass module) to provide an interior temperature reading oroutside of the vehicle to provide an exterior temperature reading.Compass module 410 and microprocessor 419 are operable to controltemperature display 423 (such as via one or more wires 426 b connectedto temperature display 423) to display an interior or exteriortemperature to the driver of the vehicle in response to the temperaturesensor. The compass module 410 thus provides a low cost temperaturedisplay to an interior rearview mirror assembly of a vehicle.Additionally, because microprocessor 419 and circuit board 430 areoperable to control temperature display 423, which is positioned atcompass module 410, a temperature display (or other display oraccessory, as discussed below) may be provided at the interior rearviewmirror assembly, without requiring any additional circuitry and controlswithin the mirror casing.

Although shown and described as providing a generally rosette shapedcompass display with four or eight illumination sources and ports forindicating a directional heading of the vehicle, clearly otherquantities or combination or arrangement of illumination sources andports of the display may be implemented without affecting the scope ofthe present invention. Also, each illumination source may not requireits own separate port, since multiple illumination sources may emitillumination or illuminate or back light respective areas of a singleport such as to form an illuminated character or icon or indicia or thelike via selective activation of multiple illumination sources. It isalso envisioned that a reconfigurable multi-pixel or multi-elementdisplay element (such as a liquid crystal or electroluminescent or lightemitting diode display element or the like) may be provided, whereineach pixel or particular groups of pixels may be independently energizedor illuminated to form the desired character or icon or symbol orindicia of the like to indicate or display the directional heading orother information to the driver or occupant of the vehicle. For example,certain pixels of a multi-pixel display (often referred to as a dotmatrix display) may be independently energized to form an “N” or “NE”indication (or any other indicia or character or icon to convey thedesired information) on the display. Each pixel of the multi-pixel arrayor display may be positioned adjacent to a respective port in thereflective element or at least some of the pixels of the multi-pixeldisplay may be positioned adjacent to a single port in the reflectiveelement. Optionally, the multi-pixel display may be positioned elsewhereat the mirror assembly (such as at the bezel portion or chin of themirror assembly) or at the accessory module, without affecting the scopeof the present invention. The pixels may be independently energized viamultiple wires connected between the individual pixels or groups ofpixels and the microprocessor (which may be located at the compassmodule or the like), or they may be independently energized via displayaddressing circuitry at the display (such as at a printed circuit boardat or adjacent to the display area), which may be powered by and incommunication with the microprocessor or the like and/or compasscircuitry (which may be located at the compass module or the like). Thepixels of the multi-pixel reconfigurable display may comprise liquidcrystal elements, vacuum fluorescent (VF) elements, electroluminescent(EL) elements, or light emitting diodes (LEDs) or the like. Themulti-pixel display thus may provide a reconfigurable pixelated arraywhich includes a plurality of pixels that may be selectively energizedto form the desired character, symbol, icon, indicia or the like toconvey the desired information to the driver or occupant of the vehicle.

Therefore, the present invention thus provides a low cost compass mirrorand establishes the display of the compass directional headings at thereflective element of the mirror assembly. The compass system may onlyrequire a power supply, such as a 12 volt power supply, from thevehicle, and does not require encoding or decoding of the signal fromthe compass circuitry to the display.

The compass module and compass system of the present invention may beimplemented as part of an interior rearview mirror assembly supplied toa vehicle manufacturer and installed in a particular vehicle whichincludes a compass mirror option. It is further envisioned that thecompass module and system may be supplied to a mirror assembler orsupplier as a kit. The kit may include a compass pod or module asdescribed above (and with appropriate mounting configuration formounting to the desired mirror mount) and a display block or circuitboard having an electrical connector and illumination sources for thedisplay (and other display devices, such as a temperature display or thelike), and may or may not include the reflective element having thecharacters or icons or indicia sandblasted, etched or otherwise formedthereon.

The mirror assembler may purchase the compass kit (and attach thedisplay block to an adapted reflective element, such as by suitableadhesives or the like, such that the illumination sources are alignedwith the respective characters formed on the reflective element) andinstall the reflective element into the housing or casing of the mirrorassembly, and mount the compass pod to the mirror mount. The connectorcable from the display may be routed through an opening in the mirrorcasing and plugged into the corresponding connector at theself-contained, stand alone, low cost compass module. An operator thusmay incorporate, such as via popping or snapping, the display andreflective element into the casing with minimal extra customization andcost to the casing and thus to the overall mirror assembly. Theillumination source block or display block (or a printed circuit boardhaving the illumination sources thereon) of the compass display may besized to fit within the interior space of standard casings, such thatminimal changes or modifications to the casing are necessary. Forexample, the case may be modified or made to have a hole or passagewayfor passing the connector cable to connect the display to the circuitboard of the compass module, but may otherwise be the same as fornoncompassized mirror assemblies.

Optionally, the compass display may be inserted into or installed orbackloaded into the mirror casing after the reflective element has beenattached thereto (such as via snapping the reflective element into thebezel portion of the casing substantially immediately after molding orheating of the casing and while the casing and bezel portion are warnand pliable), such as disclosed in U.S. provisional application Ser. No.60/471,546, filed May 19, 2003 by Uken et al. for MIRROR ASSEMBLY FORVEHICLE, which is hereby incorporated herein by reference. The compassdisplay thus may be mounted to or attached to one or more casing capportions, which may be snapped or otherwise attached to the rear portionof the casing, such that the compass display components are positionedwithin the casing and generally adjacent to or against the rear surfaceof the reflective element. The casing for the mirrors thus may comprisea common casing, whereby corresponding reflective elements and capportions (with the appropriate circuitry/components/accessories/etc.)may be installed or attached to the common mirror casings.

It is envisioned that the compass sensor (such as a magnetoresistivesensor or a magnetoinductive sensor or the like) or compass circuitry orsystem or other circuitry or system or accessory of the rearview mirrorsystem or rearview mirror assembly or accessory module of the presentinvention may be operable in communication or cooperation with circuitryand components of a global positioning system (GPS) of the vehicle.Alternately, the global positioning system of the vehicle can serve asthe directional sensing means, and thus may obviate the need for amagnetoresponsive sensor or the like in the vehicle that detects localearth's magnetic fields. As described below, the global positioningsystem of the vehicle can calculate or deduce the directional heading ofthe vehicle by deducing such from geographical positional point-to-pointdata as the vehicle moves across the earth's surface (without any regardto the local earth's magnetic field or any local vehicle magneticfield), and optionally a magnetoresponsive sensor that is responsive tothe earth's magnetic field can be used to fill in any gaps, such as mayoccur in urban canyons or the like, that may occur in the GPS-drivencalculation of the vehicle directional heading. Because themagnetoresponsive sensor, such as a magnetoresistive sensor, amagnetoinductive sensor or the like, may thus be an auxiliary sensor tothe main or primary GPS-derived compass system, algorithms andcomplexities known for compass calibration and/or for obviation ofvehicle deviating fields and/or for obviation of the affects of strayexternal magnetic anomalies (and/or for compensation of deviations invehicle magnetic fields, such as may occur as the vehicle ages or thelike) need not be utilized.

The vehicular global positioning system may comprise an in-vehicle GPSantenna and a GPS receiver/signal processor that receives a satellitecommunication to determine the geographic location of the vehicle, as isknown in the art. Such global positioning system receivers/processors,sometimes referred to as a GPS chip set, are available from varioussuppliers, such as, for example, Motorola of Schaumburg, Ill. andTrimble Navigation of Sunnyvale, Calif. By deduction of thepoint-to-point locational movement of the vehicle, the directionalheading (e.g., N, S, E, W, etc., which may be displayed as characters,icons, indicial or other indicators or the like) of the vehicle can bededuced, and this directional heading may be displayed to a driver oroccupant of the vehicle, such as by the display of the mirror system ofthe present invention. The locational data provided by the globalpositioning system to the GPS-derived compass system may includelongitudinal and latitudinal locational or position data and may includeheight or altitude data, so that a vehicle location in three dimensionalspace may be established.

In such a GPS-derived or GPS-based compass system, the directionalheading deduced is not affected by vehicle sheet metal or local magneticanomalies (such as bridges, signs, etc.). This is because thedirectional heading is deduced from electromagnetic signals, such asradio frequency signals or microwave signals or the like received fromsatellites, which are not affected by such local magnetic anomalies.Thus, traditional calibration and re-calibration of the compass systemis not needed, nor is there any need to compensate for any vehiclemagnetic field or change thereto over the lifetime of usage of thevehicle. Likewise, such a system does not require a zone input to setthe compass system to the appropriate zone, since the GPS-derived datawill indicate the geographic location of the vehicle irrespective ofwhich zone the vehicle is in. It is envisioned that such a GPS-derivedcompass system may determine or deduce the directional heading asdegrees from a particular direction, such as 42 degrees from a Northheading or the like, and thus the directional heading output of theGPS-derived compass system may be displayed as degrees to provide a moreaccurate representation to the driver or occupant of the vehicle as tothe actual directional heading of the vehicle.

Optionally, the magnetoresponsive compass sensor or circuitry responsiveto the earth's magnetic field may be operable in conjunction with theglobal positioning system of the vehicle to provide directional headingdata to the global positioning system, such as disclosed in U.S. patentapplication Ser. No. 10/422,378, filed Apr. 24, 2003 by Schofield forIMAGING SYSTEM FOR VEHICLE, now U.S. Pat. No. 6,946,978, which is herebyincorporated herein by reference. The compass sensor circuitry mayprovide such directional heading data to assist the global positioningsystem in maintaining tracking of the location of the vehicle, such asbetween waypoints or the like, when the satellite signal to the globalpositioning system is interrupted, such as may occur in cities betweentall buildings (often referred to as “urban canyons”) or the like. Othervehicle movement data may also be provided, such as vehicle speed dataor vehicle odometer data or the like, to further assist in determiningand tracking the location of the vehicle in situations where thesatellite communication to the global positioning system of the vehiclemay be temporarily interrupted or compromised. Optionally, an imagingsystem (such as described in U.S. patent application Ser. No.10/422,378, filed Apr. 24, 2003 by Schofield for IMAGING SYSTEM FORVEHICLE, which is hereby incorporated herein by reference) may be usedto further assist in determining and tracking the location of thevehicle in situations where the satellite communication to the globalpositioning system may be temporarily interrupted or compromised.

The GPS-derived compass system may provide directional heading datadeduced or calculated from point-to-point geographic positional locatorsprovided by a GPS navigational system. However, the GPS-derived compasssystem may take a period of time to lock into or deduce accurate dataafter first turning on the vehicle ignition after the vehicle has beenparked for a period of time with the ignition off. After the ignition isinitially started (sometimes referred to as a “cold start”), it can takeseveral minutes of driving until the GPS navigational system is fullyoperational and accurate. During this initial driving period, adirectional heading that the vehicle was faced in immediately prior toparking can be displayed (such previous ignition cycle heading or lastdirectional heading may be stored in an electronic memory within thevehicle when the vehicle is parked and the ignition is off). Also, wherea magnetoresponsive sensor compass system (such as a compass systemhaving a magnetoresistive sensor, a magnetoinductive sensor or the like)is used as an auxiliary or back up system to the GPS-derived compasssystem, the auxiliary magnetoresponsive sensor can provide the compasssensing during the initial period immediately after the ignitionrestarts and during the first or initial driving of the vehicle.

The magnetoresponsive sensor (typically an orthogonal pair ofmagnetoresponsive elements or the like, as known in the compass art, andsuch as described in U.S. Pat. No. 5,255,442, which is herebyincorporated herein by reference) may be calibrated during the previousignition cycle of the vehicle, and the correct calibration may beestablished by the main GPS-derived compass system during the previousignition cycle while the vehicle is driven. The auxiliary compass system(the magnetoresponsive sensor compass system) thus may be calibratedduring the prior use or movement of the vehicle via the main compasssystem (the GPS-derived compass system), and then may temporarilyfunction as the primary compass system initially after a cold startuntil such time as the main GPS-derived compass system is ready to takeover. Alternately, or additionally, the auxiliary magnetoresponsivecompass system may switch to a rapid calibration mode (such as the Cal-1mode discussed above) at the time of the initial ignition of the coldstart to quickly calibrate the magnetoresponsive sensor or sensors whenthe vehicle is first started and driven.

Thus, use of a magnetoresponsive sensor to augment or back up aGPS-derived compass system can be useful when commencing driving of thevehicle after the vehicle has been stopped and parked. Themagnetoresponsive sensor element can serve to detect the earth'smagnetic field and thus may temporarily provide a directional headingsignal until such time as the global positioning system can detectsufficient point-to-point data for the GPS-derived compass system toprovide the accurate directional heading of the vehicle. This approachcan also be useful when, for example, a vehicle turns a corner orotherwise executes a sharp directional change.

Also, and as described in U.S. patent application Ser. No. 10/422,378,filed Apr. 24, 2003, now U.S. Pat. No. 6,946,978, which is herebyincorporated herein by reference, it is envisioned that a gyroscope orgyroscopic sensor can be combined with a global positioning system(optionally, also with a magnetoresponsive sensor element included) toaugment the GPS-derived compass system when driving through urbancanyons or the like or other situations when the GPS satellite signalsare temporarily lost or obscured. In this regard, it may be advantageousto use wheel tick data, as known in the automotive art, to assist in thedetermination of the vehicle directional heading by differential compasstechniques or the like. Alternately, or in addition thereto, an assistedglobal positioning system can be utilized (whereby cellulartelecommunications may be used, as known in the art, to determine thevehicle location via triangulation of a cellular signal transmitted fromthe vehicle to cellular telephone towers or transceivers, such as bycomparing the time of flight of the signal or the like to the towers ortransceivers) to augment or supplement the GPS-derived compass system inareas where the satellite signals are temporarily lost or obscured.Optionally, where a navigational system is available in the vehicle, mapmatching techniques as known in the art can be used to augment theGPS-derived compass system. Optionally, dedicated short rangecommunication, such as to a toll system or vehicle informationcommunication system or an intelligent highway system component or thelike, can be used to supplement or augment the GPS-derived compasssystem. It is further envisioned that aspects of the imaging techniquestaught in U.S. patent application Ser. No. 10/422,378, filed Apr. 24,2003, now U.S. Pat. No. 6,946,978, which is hereby incorporated hereinby reference, may be used in connection with the GPS-derived compasssystem and/or the magnetoresponsive compass sensor or system and/or anyof the other systems or components discussed above, in order to augmentor assist the compass system or systems.

Such a GPS-derived compass system may include a termination trigger ordetection for terminating or deactivating the control of or adjustmentof a directional heading or indication to be displayed to the driver ofthe vehicle, such as via detection of activation of a reverse gearengagement. Thus, when the reverse gear of the vehicle is engaged, theGPS-derived data may be ignored, such that only forward movingGPS-derived data may be considered or utilized by the compass system ordisplay circuitry and displayed to the driver or occupant of thevehicle.

Because the global positioning system may provide altitude data, suchaltitude data may optionally be provided to the compass system ordisplay system as well. However, the altitude data currently availablevia global positioning system technology has a resolution ofapproximately +/−50 feet to +/−150 feet or thereabouts. Therefore, anexact numerical digital output or display of the deduced altitude wouldnot be practical using current global positioning system technology. Itis envisioned that the display may provide an indication of anapproximate altitude of the vehicle via illumination of one or moreicons or indicia representative of particular levels or altitudes, suchas “1000 feet above sea level”, “2000 feet above sea level” and so on(or maybe “1 kilometer above sea level”, “2 kilometers above sea level”and so on) or the like. The indicator representative of the particularaltitude that the vehicle is approaching or near or at (such as “2000feet above sea level”) may be activated or illuminated, while theindicator representative of the altitude that the vehicle is moving awayfrom (such as “1000 feet above sea level”) may be correspondinglydeactivated.

Optionally, multiple indicators or indicia for the altitude display maybe displayed as a row or column, such that multiple levels or altitudesare displayed to the driver, with the indicator or indiciarepresentative of the particular level or altitude at which the vehicleis at or near being activated or illuminated. As the vehicle altitudeincreases or decreases, the indicators or indicia may scroll or shift,such that the indicator or indicia representative of the approximatecurrent vehicle altitude remains at the center of the row or columns ofindicators/indicia. For example, the display may initially provide a rowof five indicia or indicators that are representative of “sea level”,“1000 feet above sea level”, “2000 feet above sea level”, “3000 feetabove sea level”, and “4000 feet above sea level” (with “sea level”being, for example, at the left side of the row or at the bottom of acolumn of the indicia). Initially, for example, the center indicator,which may be representative of 2000 feet above sea level, may beactivated or illuminated or otherwise highlighted. As the vehicleclimbs, the center indicator may remain illuminated, but the indicia orlabels or icons or the like of the display may shift or scroll towardone side (such as the toward left side in the present example), suchthat the indicia for “sea level” disappears and the indiciarepresentative of “5000 feet above sea level” appears at the right sideof the row. The other indicia of the display also shift toward the leftend or side, such that the left most indicia is then “1000 feet abovesea level”, and the center indicia (at the illuminated or highlightedcenter indicator) is “3000 feet above sea level”. Because the indicia orlabels may scroll as the vehicle changes altitude, the altitude displaymay only provide one indicator or illumination source, while the indiciaor icons or the like are scrolled in either direction (left-right orup-down) to match the approximate altitude of the vehicle with theindicator. Optionally, the indicator may not even be illuminated, butmay comprise a center dot or pointer or the like, with the scrollingindicia moving to align the approximate vehicle altitude with thepointer or the like.

Also, the global positioning system may provide highly accurate timedata (with an accuracy good to at least a portion of a second, such as amillisecond or nanosecond, such that a display of time down to theseconds is accurate to a single second digit) to the compass system orother circuitry or system of the mirror assembly or accessory module ormirror system of the vehicle to provide a clock setting function or toprovide a time or clock display which would provide accurate time forviewing by the driver or occupant of the vehicle. The time display maybe displayed at the reflective element of the mirror assembly or may bedisplayed at a display screen or display element at an accessory moduleor the like or may be displayed elsewhere in the vehicle, withoutaffecting the scope of the present invention. Because the GPS-derivedhighly accurate time data is fully accurate and never requiresresetting, the clock display may include hours, minutes and seconds (andeven fractions of seconds or milliseconds). Also, the GPS-derived highlyaccurate time data may, in conjunction with the GPS-derived geographic(longitude/latitude) position, figure or deduce the time zone that thevehicle is in (e.g., Eastern, Central, Mountain or Pacific time zones orthe like), and may adjust the clock output accordingly. The GPS-derivedhighly accurate time data may also provide the date, and the system mayadjust the clock output to account for daylight savings time or thelike, such as in response to the date and the current location of thevehicle. The clock display thus never needs to be reset, even when thevehicle changes time zones or when the time changes from standard timeto daylight savings time or vice versa.

It is envisioned that the global positioning system may also provide avehicle speed or average vehicle speed (such as in miles per hour orkilometers per hour) by determining the distance traveled by the vehicleduring a particular period of time. The distance traveled may bedetermined via deduction of point-to-point data pertaining to thelocational movement of the vehicle. Optionally, the OPS-derived systemmay display an odometer function, such as trip odometer function whichmay indicate the distance traveled by the vehicle since the last timethe odometer function was reset. Optionally, the GPS-derived system maydisplay a timer function or elapsed time from the start of a trip (orfrom when the timer function is activated) to a particular waypoint ordestination (or to when the timer function is stopped or deactivated).Optionally, the GPS-derived system may provide a navigational functionor may be in communication with a GPS-derived navigational system, suchas a navigational system of the types described in U.S. Pat. No.6,477,464, and U.S. provisional applications, Ser. No. 60/405,392, filedAug. 23, 2002 by McCarthy for VEHICLE NAVIGATION SYSTEM FOR USE WITH ATELEMATICS SYSTEM; and Ser. No. 60/406,166, filed Aug. 27, 2002 byTaylor et al. for VEHICLE NAVIGATION SYSTEM FOR USE WITH A TELEMATICSSYSTEM, which are hereby incorporated herein by reference.

It is further envisioned that the global positioning system of thevehicle may also provide directional heading data and/or vehicleattitude data to the magnetoresponsive compass sensor circuitry orsystem to assist in calibration of the compass sensor circuitry orsystem. The global positioning system of the vehicle may also providezone data to the compass sensor circuitry to automatically indicate thezone in which the vehicle is located. In such an application, themagnetoresponsive compass sensor circuitry may provide the directionalheading data for displaying the directional heading to the driver of thevehicle, while the GPS-derived directional heading may be auxiliary tothe magnetoresponsive compass sensor-derived directional heading and maybe used to fill in gaps in the magnetoresponsive compass sensor dataand/or to calibrate the magnetoresponsive compass sensor circuitry orsystem. As discussed above, however, the primary vehicular compasssystem may be a GPS-derived compass system, and the magnetoresponsivecompass sensor circuitry may be auxiliary to the GPS-derived compasssystem and may function to provide gap filling directional heading datato the GPS-derived compass system.

When a global positioning system is used to augment a compass sensorsystem utilizing a magnetoresponsive sensor element, or when amagnetoresistive sensor element is used to fill in the gaps of or assistfunctioning of a GPS-derived compass system, the GPS-derived systemcomponent and the magnetoresponsive sensor element may be substantiallyco-located (such as within a windshield electronic module (such as thetype disclosed in U.S. patent application Ser. No. 09/793,002, filedFeb. 26, 2001, now U.S. Pat. No. 6,690,268, which is hereby incorporatedherein by reference)) or they may be in disparate locations of thevehicle (with interconnection preferably provided via a vehicularnetwork, such as a CAN, LIN, MOST or similar vehicular networkingprotocol/systems or the like).

The present invention thus may provide a mirror system or mirror mountedvehicle information display system, which is operable to displayinformation pertaining to the directional heading of the vehicle, thespeed of the vehicle, the distance traveled by the vehicle, the altitudeof the vehicle, the highly accurate time and date, and/or the like, allof which information or data may be obtained or derived from the globalpositioning system of the vehicle. Optionally, the display fordisplaying the clock, vehicle speed, etc. may be provided at or belowthe mirror reflective element (or elsewhere at the mirror assembly) orat an accessory module or electronic module or pod or the like, and mayinclude a menu or selection list for a user to access to select whichinformation is to be displayed at the display.

With reference to FIG. 13, an interior rearview mirror system 500 isshown which comprises a GPS-derived compass system (comprising of aglobal positioning system 551, which may comprise a GPS antenna 552 anda GPS receiver/signal processor 554) and a magnetoresponsive auxiliaryor back up compass sensor 518. A microprocessor 519 may receive datafrom the global positioning system and may generate directional headingdata or information for displaying at a vehicle information display 520,while the magnetoresponsive compass sensor (for example, amagnetoresistive compass sensor or the like) provides an auxiliarycompass sensor and is available for filling in gaps in the data and/orassisting in providing directional data after cold starts of thevehicle, as discussed above. Preferably, direction indicative signals asgenerated by the auxiliary compass sensor 518 is fed to and processed bymicroprocessor 519. The microprocessor may temporarily process thedirection indicative signals generated by the auxiliary compass sensor518 to generate directional information for displaying at display 520when the locational data generated by the global positioning system 551is compromised. The GPS-derived compass system of mirror system 500 thusmay be the primary or main compass system and may provide or display thedirectional heading of the vehicle (as derived via the globalpositioning system) at display 520, while the magnetoresponsive compasssensor 518 may provide the auxiliary compass system or gap fillingfunction, and thus may provide a back up compass sensor for theGPS-derived compass system.

In the illustrated embodiment, mirror system 500 includes an accessorymodule 510, which includes a base portion 510 a and a head portion 510b, and an interior rearview mirror assembly 514. Head portion 510 b ofaccessory module 510 may include a printed circuit board 530, whichincludes the magnetoresponsive compass sensor 518 (such as one or moremagnetoresistive sensors, magnetoinductive sensors or the like) andmicroprocessor 519. The microprocessor 519 is in communication withglobal positioning system 551 and receives signals from the globalpositioning system and generates data or information (such as describedabove) to be displayed at information display 520. As discussed above,by deduction of the point-to-point locational movement of the vehicle,the directional heading (e.g., N, S, E, W, etc.) of the vehicle can bededuced, and this directional heading information (such as N, S, E, W,etc. characters or other icons, indicia or indicators or the like) maybe displayed to a driver or occupant of the vehicle, such as by display520 of mirror system 500.

The printed circuit board 530 may include or may be in communicationwith information display 520, which may comprise multi-functionaldisplay, and which may comprise a multi-pixel reconfigurable vehicleinformation display, such as described above. As shown in FIG. 13, themulti-functional vehicle information display 520 may be positioned athead portion 510 b of the accessory module 510 and may be viewable abovethe mirror assembly 514. Information display 520 may be selectivelyoperable to display information from one or more of the accessories ofthe accessory module or from other accessories or systems of the mirrorassembly or mirror system or of the vehicle. For example, user-actuablebuttons 544 (preferably readily accessible at or near the display 520)may be used for menu item selection (such as via stepping throughmultiple menu items to make a desired selection) of one or moreaccessories or functions that the user desires to have displayed atdisplay 520. The menu items to be stepped through via the user-actuablecontrols or buttons 544 may at least include a compass octant directiondisplay (e.g., N, S, E, W, etc.), a compass angle direction or heading,a clock display (preferably a highly accurate clock display includingdisplay accuracy to a second), a vehicle velocity display (e.g., mph,kph, etc.), an odometer display, a trip odometer display, an elapsedtime display and/or the like. The user may actuate or depress thecontrol or button multiple times to view the different availablefunctions or displays, and may then select the desired display when thatparticular display is shown in the menu.

Accessory module 510 may further include a photosensor 542 to determinethe ambient light level surrounding the mirror system, whereby themicroprocessor or other controls or circuitry may dim or adjust theintensity of the illumination sources or pixels of display 520 inresponse to ambient sensing photosensor 542, in order to provide fordimming of the output of display 520 in darkened lighting conditions,such as at nighttime conditions, in order to reduce the intensity ofdisplay 520 to reduce glare and distraction and annoyance to the driverof the vehicle.

Accessory module 510 may be generally fixedly mounted at a mountingbutton 512 c at the interior surface of the windshield 513 a of avehicle, while interior rearview mirror assembly 514 may include amirror mount 512 b which mounts to a second mounting button orattachment member 512 d at the accessory module 510, such as in themanner described in U.S. patent application Ser. No. 10/355,454, filedJan. 31, 2003 by Schofield et al. for VEHICLE ACCESSORY MODULE, now U.S.Pat. No. 6,824,281, which is hereby incorporated herein by reference. Afastener or set screw 512 e or the like may be provided to secure theaccessory module 510 to the mounting button 512 c. Mirror assembly 514includes a casing 515 and a reflective element 516 adjustably mounted tomirror mount 512 b, such as via a mounting arm 512 a and a double ballor single ball mounting arrangement, as is known in the mirror art.

The upper or head portion 510 b of accessory module 510 includes one ormore accessories or printed circuit boards 530, 531 positioned therein.Head portion 510 b of accessory module 510 a may be pivotably or movablymounted to the upper end of the base portion 510 a of accessory module510, such as at a pivot or swivel joint 510 c, and such as disclosed inU.S. patent application Ser. No. 10/355,454, referenced above.Alternatively, head portion 510 b may be fixedly mounted to base portion510 a. Head portion 510 b may extend generally over the mirror case 514to facilitate viewing and accessing the information display 520 and/oruser actuable buttons or controls 544, 545. In addition to themicroprocessor 519 and magnetoresponsive compass sensor 518, headportion 510 b may further include one or more accessories on the printedcircuit boards 530, 531, such as, for example, a forward facing cameraor imaging sensor 546 (such as for a rain sensor system, an automaticheadlamp control system, a lane departure warning system, or any othervision or imaging system of the vehicle, such as the types discussedbelow), a microphone 548 (which may be positioned at a lower portion ofthe head portion 510 b and generally above the mirror casing 515 asshown in FIG. 13), garage door opening circuitry 550 (and associatedcontrols or buttons 545 for actuating the garage door openingtransmitter or the like), and/or any other vehicular accessories orsystems or functions or the like. The bead portion 510 b may includeuser actuable controls or buttons 545 for selecting or activating anddeactivating or controlling or adjusting one or more of the accessories.

Optionally, and as shown in FIGS. 14 and 15, the vehicle informationdisplay 520 of a mirror system 500′ may be positioned at the reflectiveelement 516′ of a mirror assembly 514′ (FIG. 14), or the vehicleinformation display 520 of a mirror system 500″ may be positioned at abezel portion or chin portion 515 a (FIG. 15) of a mirror assembly 514″(optionally, the display may otherwise be positioned elsewhere aroundthe bezel portion, such as, for example, at the eyebrow portion of themirror assembly or the like), while the controls and/or circuitry forthe display system may be positioned within the mirror casing 515 (suchas at or near the display 520) and/or at the accessory module orwindshield electronic module 510′ or the like remote from the mirrorassembly 514′, 514″. The mirror assemblies and accessory modules ofFIGS. 13-15 are otherwise substantially similar to one another, suchthat a detailed discussion of the similar components will not berepeated for each assembly. The common components of the accessorymodules and mirror assemblies shown in FIGS. 13-15 are shown with commonreference numbers.

As discussed above, the mirror assembly 514′, 514″ may mount on amounting button 512 d positioned at or protruding from an accessorymodule or windshield electronic module 510′ which, in turn, may bemounted to an interior portion of the vehicle, such as to a mountingbutton 512 b at the interior surface of the windshield 513 a or to theheadliner 513 b or overhead console or the like. In such applications,it is envisioned that the communication link between the controls andthe display system may be provided by a wireless data communication link556 (such as a wireless communication link of the type disclosed in U.S.patent application Ser. No. 09/839,678, filed Apr. 20, 2001 by McCarthyet al. for VEHICLE MIRROR ASSEMBLY COMMUNICATING WIRELESSLY WITH VEHICLEACCESSORIES AND OCCUPANTS, now U.S. Pat. No. 6,693,517, which is herebyincorporated herein by reference). The wireless data communication link556 may include a transceiver 556 a at the accessory module 510′, andanother transceiver 556 b at the mirror casing 515, such as at a printedcircuit board 533 positioned at or along a rear surface of thereflective element. The wireless data communication transceiver 556 amay emit a signal, such as an infrared signal or a radio frequency (RF)signal or the like, from the windshield electronic module or the like tothe transceiver 556 b at the mirror housing to communicate data orcontrol functions thereto. For example, the wireless communication linkmay communicate data from the microprocessor 519 to the display ordisplay system 520, or may communicate data from the microprocessor (orfrom the global positioning system or other system or accessory) toother circuitry or accessories or displays positioned at the mirrorassembly. The mirror assembly then only requires a power supply, such asa 12 volt power supply via a wire from the vehicle or accessory module,to power the functions or accessories or circuitry at the mirrorassembly (optionally, the mirror assembly may include a battery powersource or supply to obviate the need for a separate power connection).The wireless or infrared link thus avoids the need for a multi-wire datacable or the like between the accessory or electronic module and themirror housing to provide communication and control of the accessories,functions or circuitry at the mirror assembly. The wirelesscommunication link thus may allow the vehicle manufacturer to purchase acommon windshield electronic module having the wireless or infraredlink, and then associate the module with the appropriate display device,which may be at the mirror housing or at the instrument panel or at theoverhead console or the like, via adjusting the aim or direction of thewireless link transceiver at the module so it is properly received by acorresponding transceiver at the display device. The wireless link thusfacilitates interchangeability of the electronic modules and mirrorassemblies, depending on the desired accessories, features or functionsof the mirror system. For embodiments where a gyroscope is included toaugment the global positioning system during periods when satelliteinputs may be temporarily lost or compromised, the gyroscope can provideexact navigational guidance, and thus is a preferred inclusion should aturn-by-turn navigational feature or function be used or provided withinthe vehicle, such as navigation systems of the types disclosed in U.S.Pat. No. 6,477,464, and U.S. provisional applications, Ser. No.60/405,392, filed Aug. 23, 2002 by McCarthy for VEHICLE NAVIGATIONSYSTEM FOR USE WITH A TELEMATICS SYSTEM; and Ser. No. 60/406,166, filedAug. 27, 2002 by Taylor et al. for VEHICLE NAVIGATION SYSTEM FOR USEWITH A TELEMATICS SYSTEM, which are hereby incorporated herein byreference.

As shown in FIGS. 14 and 15, the mirror case 515 may include otheraccessories or functions on the printed circuit board 533, such as aphotosensor or the like 558 (such as for determining ambient lightlevels or for determining glare at the reflective element),electrochromic reflective element controls or circuitry 560 (forapplications having an electrochromic reflective element), or otheraccessories or functions or features which may desirably be located ator within the mirror case. The sensors or accessories or controls may bepositioned behind the mirror reflective element or may be positionedelsewhere at or within the casing, such as at the bezel or chin portion515 a of the mirror case 515. As shown in FIG. 14, the vehicleinformation display 520 may be positioned at the reflective element516′, and may be operable to project or emit illumination of informationthrough the reflective element (such as through a transflectiveelectrochromic reflective element such as discussed below or through aport or transparent window or region formed or etched in the reflectivecoating of the reflective element) for viewing by the driver or occupantof the vehicle. Optionally, as shown in FIG. 15, the vehicle informationdisplay 520 may be positioned at a chin or bezel portion 515 a of themirror case 515, and may include one or more user actuable controls orbuttons at or near the information display. Optionally, as discussedabove, the information display may be located at an accessory module orpod or the like at or near the interior rearview mirror assembly. Thevehicle information display thus is associated with or adjacent to theinterior rearview mirror assembly.

The information display 520 may comprise any of the types of displaysdescribed above, and may have multiple independently energizable LEDs,or may comprise a multi-pixel reconfigurable display, or the like.Optionally, and in addition to the vehicle information display 520 atthe mirror assembly, the head portion 510 a of the accessory module 510′may also include another information display 521 a (FIGS. 14 and 15)and/or the circuit board 533 at the reflective element may includeanother information display 521 b (which may project information throughthe reflective element, such as through a substantially transparentwindow formed in the reflective coating or through an electro-opticreflective element, such as a transflective electro-optic reflectiveelement) to display other information to the driver or occupant of thevehicle.

Although shown and described as being positioned at an accessory moduleof a mirror system, clearly, the components of the global positioningsystem of the vehicle (i.e., the antenna and/or receiver/processor) canbe located anywhere in the vehicle, such as in an instrument panel area,console, overhead console, or elsewhere, without affecting the scope ofthe present invention. Communication from the global positioning systemto the upper windshield region at or adjacent to the rearview mirrorassembly can be via a wire connection or a wireless communication.Preferably, the communication is via a bus or a vehicle networkconnection, such as a CAN, LIN, MOST or similar vehicular networkingprotocol/systems or nodes or the like, such as Bluetooth, SCP, UBP,J1850, CAN J2284, Fire Wire 1394 and/or the like. The microprocessorand/or display may be positioned at or adjacent to the rearview mirrorassembly, such as in the mirror assembly or in the accessory module orpod or the like.

Also, although shown and described as having an accessory module and aninterior rearview mirror assembly mounted to the accessory module (asshown in FIGS. 13-15), the mirror system of the present invention mayinclude other forms of accessory modules or pods, such as a unitary podor module, or a pod or module which attaches to the mirror mount (whichin turn mounts to or attaches to a mounting button at the windshield orheadliner or overhead console or other interior portion of the vehicle),without affecting the scope of the present invention.

Optionally, the printed circuit board of the compass or mirror system(such as a printed circuit board of a compass module or pod or a printedcircuit board of the mirror assembly) of the present invention mayinclude another display element along or partially along an edge of theboard and may include one or more user-actuatable controls or buttonsnear or adjacent to the display element. The display element may be anytype of display, such as a vacuum fluorescent (VF) display, a lightemitting diode (LED) display, an electroluminescent (EL) display, aliquid crystal display (LCD), a video screen display or the like, andmay be operable to display various information (as discrete characters,icons or the like, or in a multi-pixel manner) to the driver of thevehicle, such as passenger side inflatable restraint (PSIR) information,tire pressure status, and/or the like. The buttons may be for actuatingor controlling various accessories or controls or components associatedwith the vehicle, such as for a compass calibration setting or zonesetting, a telematics actuation, a garage door opener, an electronictoll control (such as disclosed in U.S. patent application Ser. No.09/793,002, filed Feb. 26, 2001 by Schofield et al. for VIDEO MIRRORSYSTEMS INCORPORATING AN ACCESSORY MODULE, now U.S. Pat. No. 6,690,268,which is hereby incorporated herein by reference), and/or the like, ormay be for switching the display between various functions or modes,without affecting the scope of the present invention. The mirror casingmay include appropriate openings, such that the display element isvisible through one opening, while the buttons or controls may partiallyprotrude through other corresponding openings when an appropriatecircuit board is installed within the mirror casing.

Optionally, the printed circuit board, or the mirror assembly (or thecompass module or an accessory module associated with the mirrorassembly), may include other accessories, such as a rain sensor (such asthe type disclosed in commonly assigned U.S. Pat. Nos. 6,320,176;6,353,392 and 6,313,454, which are hereby incorporated herein byreference), an image sensor (such as a video camera, such as a CMOSimaging array sensor, a CCD sensor or the like, such as the typesdisclosed in commonly assigned, U.S. Pat. Nos. 5,550,677; 6,097,023 and5,796,094, which are hereby incorporated herein by reference), atemperature sensor (such as a contact temperature sensor for measuringthe temperature at or of the windshield), an antenna, or any othersensor or device. For example, the mirror assembly may include a forwardfacing video image sensor or system, which may include an intelligentrain sensor (such as the type disclosed in commonly assigned U.S. Pat.Nos. 6,320,176; 6,353,392 and 6,313,454, which are hereby incorporatedherein by reference), an image or vision system (including an imagingsensor, such as a video camera, such as a CMOS imaging array sensor, aCCD sensor or the like, such as the types disclosed in commonlyassigned, U.S. Pat. Nos. 5,550,677; 6,097,023 and 5,796,094, and U.S.patent application Ser. No. 10/422,378, filed Apr. 24, 2003 by Schofieldfor IMAGING SYSTEM FOR VEHICLE, now U.S. Pat. No. 6,946,978, which arehereby incorporated herein by reference), an intelligent headlampcontroller (such as the type disclosed in U.S. Pat. No. 5,796,094 and/orin U.S. patent application Ser. No. 10/355,454, filed Jan. 31, 2003 bySchofield et al. for VEHICLE ACCESSORY MODULE, now U.S. Pat. No.6,824,281, which are hereby incorporated herein by reference), anintelligent lane departure warning system, such as the type disclosed inU.S. patent application Ser. No. 10/427,051, filed Apr. 30, 2003 byPawlicki et al. for OBJECT DETECTION SYSTEM FOR VEHICLE, now U.S. Pat.No. 7,038,577, which is hereby incorporated herein by reference, and/orthe like. In applications where the mirror assembly includes or isassociated with an automatic headlamp control system, it is envisionedthat the display of the mirror system may include or provide a highbeam/low beam indicator (such as an icon or indicia indicative of thehigh beams being activated, such as a blue headlamp indicia or the like)to indicate the status of the high beams of the vehicle to the driver oroccupant of the vehicle.

Optionally, the mirror assembly or compass or accessory or electronicmodule of the present invention may include one or more displays, suchas a text display, an icon display, a display on demand type display(such as may be implemented with a transflective reflective element,such as described in U.S. patent application Ser. No. 09/793,002, filedFeb. 26, 2001, entitled VIDEO MIRROR SYSTEMS INCORPORATING AN ACCESSORYMODULE, now U.S. Pat. No. 6,690,268, and in U.S. Pat. Nos. 5,668,663 and5,724,187, the entire disclosures of which are hereby incorporated byreference herein), such as a video or touch screen interface display, orthe like, and/or one or more sensors or other accessories, such as abiometric imager, such as for fingerprint authentication or the like, aninfrared sensor, such as a zonal temperature sensor, such as suitablefor an auto climate control, a forward facing image sensor, such asdescribed above, a rearward facing image sensor (such as for biometricimaging (such as for face recognition, iris recognition or the like),seat height or position detection, drowsiness detection,safety/restraints object detection and position, emergency responseimage capture system, intrusion detection or the like), an electronicfield sensor (such as the type disclosed in commonly assigned U.S.patent application Ser. No. 09/992,119, filed Nov. 14, 2001 by McCarthyet al. for VEHICLE COMPARTMENT OCCUPANCY DETECTION SYSTEM, now U.S. Pat.No. 6,768,420, which is hereby incorporated herein by reference), amicrophone (such as the type disclosed in commonly assigned U.S. Pat.Nos. 6,243,003 and 6,278,377, and/or U.S. patent application Ser. No.09/466,010, filed Dec. 17, 1999 by DeLine et al. for INTERIOR REARVIEWMIRROR SOUND PROCESSING SYSTEM, now U.S. Pat. No. 6,420,975, which arehereby incorporated herein by reference), which may be mounted at anupper portion of the mirror assembly and/or at the module. The displayand/or accessories may be associated with a communication system, aspeaker, a telematics module (which may include a GPS module, a wirelesscommunication module, an human/machine interface (HMI), a display, suchas an LED display, a dot matrix display, an alpha numeric display, avideo display or the like, and/or a microphone, which may be operablefor speech or voice recognition, noise reduction or noise cancellation),a humidity sensor, a remote keyless entry sensor, a tire pressuremonitoring system (TPMS), an electronic toll collection sensor, anintelligent headlamp control, user interface controls (such as buttons,switches or the like for controlling various accessories of the vehicle,such as a sunroof, a communication system, lamps, security systems,displays or the like) or any other accessories, sensors, lights,indicators, displays or the like which may be suitable for mounting orpositioning at or within the interior rearview mirror assembly oraccessory module. The interior rearview mirror assembly and/or compassor accessory module may also provide for glare reduction characteristicsof the reflective element of the rearview mirror assembly.

The accessories or components of the interior rearview mirror assemblyor the compass or accessory or electronic module may be connected to thevehicle electronic or communication systems and may be connected viavarious protocols or nodes, such as Bluetooth, SCP, UBP, J1850, CANJ2284, Tire Wire 1394, MOST, LIN and/or the like, depending on theparticular application of the interior rearview mirror assembly and/orcompass module of the present invention. The interior rearview mirrorassembly and/or compass module may be electronically integrated with thevehicle electrical and/or control systems. For example, the interiorrearview mirror assembly may connect to a sunroof control, rain sensorcontrol, mass motion sensor, roof lighting control, microphone/cellphone control, climate control, and/or the like.

The interior rearview mirror assembly and/or accessory module may alsoinclude user interface controls, such as buttons, switches or the like,displays, indicators, microphones, speakers or the like. Some of thesemay be provided at or along a display or interface area at or above themirror.

The interior rearview mirror assembly and/or the compass module of thepresent invention may include lights, and may be a modular rearviewmirror assembly, such as described in U.S. Pat. No. 6,124,886, which ishereby incorporated herein by reference, or may have various otheraccessories, such as disclosed in U.S. Pat. No. 6,222,460, which ishereby incorporated herein by reference.

Optionally, the interior rearview mirror assembly or compass oraccessory module of the present invention may include a network bus,such as a CAN bus or a LIN bus, such as disclosed in U.S. Pat. No.6,291,905, which is hereby incorporated herein by reference. The networkbus may be operable to communicate with other systems of the vehicle,such as with accessories or elements of an accessory module, such as anaccessory module of the type disclosed in commonly assigned U.S. Pat.Nos. 6,243,003; 6,278,377 and 6,420,975; U.S. patent application Ser.No. 10/054,633, filed Jan. 22, 2002 by Lynam et al. for VEHICULARLIGHTING SYSTEM, now U.S. Pat. No. 7,195,381; U.S. patent applicationSer. No. 10/355,454, filed Jan. 31, 2003 by Schofield et al. for VEHICLEACCESSORY MODULE, now U.S. Pat. No. 6,824,281; and/or InternationalPublication No. WO 01/64481, published Sep. 7, 2001, which are allhereby incorporated herein by reference.

Optionally, it is envisioned that the compass system of the presentinvention may be implemented with an electrochromic rearview mirrorassembly, preferably utilizing a solid polymer matrix electrochromicmedium, such as described in U.S. Pat. No. 5,910,854, which is herebyincorporated herein by reference. The network bus of the interiorrearview mirror assembly may then be in communication with the reversingsystem of the vehicle, such that the interior rearview mirror assemblyknows when the vehicle is shifted into reverse. The bus may then beoperable to disable the electrochromic dimming of the mirror when thevehicle is in reverse, as is desired and known in the art.

The mirror system or interior rearview mirror assembly and/or compass oraccessory module of the present invention may then includeelectrochromic control circuitry for controlling the reflectivity of anelectrochromic mirror. The circuitry may include a rearward viewingglare detector or sensor and a forward viewing and/or sideward viewingambient light detector or sensor, such as described in U.S. Pat. No.4,793,690, which is hereby incorporated herein by reference, or mayinclude a single sensor, such as described in U.S. Pat. No. 5,193,029,which is hereby incorporated herein by reference. The output of thecircuitry may control an outside electrochromic mirror as well as theinterior rearview electrochromic mirror. It is further envisioned thatthe circuitry may control an outside electrochromic mirror, while theinterior rearview mirror assembly may be a prismatic mirror, withoutaffecting the scope of the present invention.

Further, automatic dimming circuitry used in the electrochromic mirrorassembly and/or in the compass module of the present invention mayutilize one or more (typically two) photosensors to detect glaringand/or ambient lighting. For example, a silicon photosensor, such as aTSL235R Light-to-Frequency converter (available from Texas AdvancedOptoelectronic Solutions Inc. of Plano, Tex.), may be used as such aphoto sensor. Such light-to-frequency converters comprise thecombination of a silicon photodiode and a current-to-frequency converteron a single monolithic CMOS integrated circuit.

The mirror system of the present invention may include use of a blue orultraviolet light emitting LED that emits UV and/or blue radiation(typically below about 400 nm in wavelength or thereabouts) into aspecialized filter material (interposed as described above between thelight source and the rear of the reflective element), and with thespecialized filter material (typically a polymeric film or layer)including an organic or inorganic compound that fluoresces and/orphosphoresces in a color different than the color emitted by the LEDlight source. Thus, for example, a blue or blue-green fluorescing moietycan be included in the filter that, when irradiated with radiation froman ultraviolet LED, glows with a blue or blue-green color so that thedriver, when viewing the “N” cardinal direction, for example, as etchedor otherwise created or formed on the mirror reflective element, sees“N” in a blue or blue-green color. Likewise for other colors in thevisible spectrum.

It is further envisioned that the interior rearview mirror assembly mayinclude a transflective one way mirror element, such as disclosed incommonly assigned U.S. patent application Ser. No. 10/054,633, filedJan. 22, 2002 by Lynam et al. for VEHICULAR LIGHTING SYSTEM, now U.S.Pat. No. 7,195,381, which is hereby incorporated herein by reference.Preferably, the mirror reflective element (behind which a video displayscreen may be disposed so that the image displayed is visible by viewingthrough the mirror reflective element) of the interior mirror assemblycomprises a transflective mirror reflector such that the mirrorreflective element is significantly transmitting to visible lightincident from its rear (i.e. the portion furthest from the driver in thevehicle), with at least about 15% transmission preferred, at least about20% transmission more preferred and at least about 25% transmission mostpreferred, while simultaneously, the mirror reflective element issubstantially reflective to visible light incident from its front (i.e.the position closest to the driver when the interior mirror assembly ismounted in the vehicle), with at least about 60% reflectance preferred,at least about 70% reflectance more preferred and at least about 75%reflectance most preferred. Preferably, a transflective electrochromicreflective mirror element is used (such as is disclosed in U.S. patentapplication Ser. No. 09/793,002, filed Feb. 26, 2001, entitled VIDEOMIRROR SYSTEMS INCORPORATING AN ACCESSORY MODULE, now U.S. Pat. No.6,690,268 and in U.S. Pat. Nos. 5,668,663 and 5,724,187, the entiredisclosures of which are hereby incorporated by reference herein) thatcomprises an electrochromic medium sandwiched between two substrates.

The interior rearview mirror assembly may include a display on demand(DOD) display (such as disclosed in commonly assigned, U.S. patentapplication Ser. No. 10/054,633, filed Jan. 22, 2002 by Lynam et al. forVEHICULAR LIGHTING SYSTEM, U.S. patent application Ser. No. 09/793,002,filed Feb. 26, 2001, entitled VIDEO MIRROR SYSTEMS INCORPORATING ANACCESSORY MODULE, now U.S. Pat. No. 6,690,268 and in U.S. Pat. Nos.5,668,663 and 5,724,187, the entire disclosures of which are herebyincorporated by reference herein) which may comprise two or moredisplays located in the mirror assembly. Optionally, when the left turnsignal is turned on, a blind spot/lane change aid camera view or hazardindication may be displayed in the mirror (preferably via a display ondemand indicia or display).

Also, the interior rearview mirror system may include ultra smallinformation displays, such as are disclosed in U.S. patent applicationSer. No. 10/225,851, filed Aug. 22, 2002 by Burgner for VEHICLEINFORMATION DISPLAY, now U.S. Pat. No. 6,847,487, the entire disclosureof which is hereby incorporated by reference herein. Such ultra-smalldisplays may be of a transmissive-type or a reflective type. Forexample, the ultra small liquid crystal display (LCD) available fromKopin Corporation of Taunton, Mass. is a transmissive type. KopinCorporation utilizes silicon-on-insulator SOI wafers to buildtransmissive displays. Kopin Corporation's product utilizes thinmonocrystal silicon thin film transistors Si-TFT of several micronspeeled off from the circuit board to filter out light, and employs afield sequential method, which shows images in accordance withsequentially changing red, green, and blue. The display has a highdegree of transmissivity because it does not need color filters. Imagequality depends on color purity of the light emitting diode used as theillumination source.

Therefore, the compassized interior rearview mirror system of thepresent invention provides for the addition or implementation of acompassized reflective element within a casing of an interior rearviewmirror assembly, with minimal invasiveness if any at all to the overallcomplete mirror assembly design. The compass system and reflectiveelement combination of the present invention may allow for easyinstallation of the compass system within the mirror casing, since thecompass system may be installed as the reflective element is snappedinto place at or within the mirror casing. The compass system may thusbe implemented within a prismatic interior rearview mirror assembly atgenerally the same cost, with respect to design and tooling costs andthe like of the mirror assembly, as a non-compassized mirror assembly.The compass system and printed circuit board may thus be implemented ina low cost, double ball mounted prismatic mirror assembly, therebyproviding a compass system for non-luxury vehicles.

Additionally, the accessory module and display at an interior rearviewmirror assembly in accordance with the present invention provides forthe addition or implementation of a compassized reflective elementwithin a casing of a mirror assembly, with minimal invasiveness if anyat all to the overall complete mirror assembly design. The compasssystem and reflective element combination of the present invention mayallow for easy installation of the compass system at the mirror mount,while the display may be positioned at the reflective element. Thecompass circuitry may be in electrical communication with the displayillumination sources or light emitting diodes and may be operable toenergize each of the illumination sources via energizing a single wireassociated with each illumination source. The compass or accessorymodule of the present invention may also include electro-optic controlcircuitry for automatically dimming an electro-optic or electrochromicreflective element. Such an electro-optic reflective element may beprovided within the mirror housing and may be connected to the controlcircuitry of the compass module to provide electro-optic function to alow cost mirror assembly, which otherwise does not include suchcircuitry. The compassized mirror system may thus be implemented in alow cost, double ball mounted prismatic mirror assembly, therebyproviding a compass system for non-luxury vehicles.

The present invention may also provide a GPS-derived compass system fordeducing or providing and displaying directional heading data orinformation to a driver or occupant of the vehicle. The mirror systemmay include a magnetoresponsive sensor which may function as anauxiliary or back up to the GPS-derived compass system when the globalpositioning system of the vehicle is not generating an appropriatesignal or input to the GPS-derived compass system. The auxiliary compasssensor thus ensures consistency of the directional heading informationbeing displayed. Because the GPS-derived compass system may function asthe primary compass system and may function to calibrate themagnetoresponsive sensor, compass control circuitry and calibrationalgorithms and circuitry are not required. The GPS-derived compasssystem may extract or derive other data or information from the globalpositioning system of the vehicle and may selectively display such othervehicle information to the driver or occupant of the vehicle.

Changes and modifications in the specifically described embodiments canbe carried out without departing from the principles of the presentinvention, which is intended to be limited only by the scope of theappended claims, as interpreted according to the principles of patentlaw.

1. A video mirror system for a vehicle, said video mirror systemcomprising: an interior rearview mirror assembly having a mirror housingand a transflective reflective element; wherein said mirror housing isadjustably mounted at an interior portion of the vehicle via a doublepivot mounting arrangement; wherein said transflective reflectiveelement comprises a transflective mirror reflector that is partiallytransmissive of light and partially reflective of light incidentthereon; wherein adjustment of said mirror housing via said double pivotmounting arrangement adjusts a rearward field of view of saidtransflective reflective element when said interior rearview mirrorassembly is normally mounted in a vehicle equipped with said videomirror system; a video display screen disposed in said mirror housingand behind said transflective mirror reflector of said transflectivereflective element, wherein information displayed by said video displayscreen is viewable by a driver of the equipped vehicle viewing throughsaid transflective mirror reflector of said transflective reflectiveelement when said video display screen is activated and wherein, whensaid video display screen is not activated, the presence of said videodisplay screen behind said transflective mirror reflector of saidtransflective reflective element is substantially not discerned by adriver of the equipped vehicle normally viewing said transflectivereflective element when operating the equipped vehicle; a compass sensordisposed within said mirror housing and behind said transflectivereflective element, wherein said compass sensor adjusts in tandem withadjustment of the rearward field of view of said transflectivereflective element; compass circuitry responsive to said compass sensorfor determining a directional heading of the vehicle; a compass displayin the vehicle for displaying directional heading information to thedriver of equipped vehicle; and wherein said compass circuitry at leastpartially compensates for movement of said compass sensor caused byadjustment of said mirror housing via an algorithm processed by amicroprocessor.
 2. The video mirror system of claim 1 further comprisinga physical mount for mounting said compass sensor at said transflectivereflective element.
 3. The video mirror system of claim 2, wherein saidcompass circuitry automatically at least partially compensates for adeviating magnetic field of the vehicle and generates a compensatedsignal indicative of the directional heading of the vehicle.
 4. Thevideo mirror system of claim 2, wherein said compass sensor comprisesfirst and second magnetoresponsive sensing elements.
 5. The video mirrorsystem of claim 4, wherein said physical mount is configured to orientsaid first magnetoresponsive sensing element to be substantiallyparallel to a direction of travel of the vehicle and said secondmagnetoresponsive sensing element to be substantially orthogonal to thedirection of travel of the vehicle when said reflective element is at aselected angled.
 6. The video mirror system of claim 1, wherein saidcompass circuitry enters a rapid compensating mode in response to anignition cycle of the vehicle.
 7. the video mirror system of claim 6,wherein said compass circuitry automatically exits said rapidcompensating mode and enters a less aggressive calibration mode thatdistinguishes the Earth's magnetic field from magnetic anomalies andnon-abrupt changes in the vehicle magnetic signature.
 8. The videomirror system of claim 7, wherein said compass circuitry automaticallyexits said rapid compensating mode after a predetermined period of timehas elapsed since the ignition cycle.
 9. The video mirror system ofclaim 1, wherein said compass display is at said interior rearviewmirror assembly and is disposed in said mirror housing and comprises aplurality of illumination sources positioned behind said transflectivereflective element, said compass circuitry energizing said illuminationsources to convey directional heading information to the driver of thevehicle.
 10. The video mirror system of claim 9, wherein said compassdisplay is operable to at least one of directly energize each of saidillumination sources independently and directly energize two or more ofsaid illumination sources in combination to provide illumination toconvey the directional information to the driver of the vehicle.
 11. Thevideo mirror system of claim 1 further comprising a global positioningsystem that is operable to determine a geographical location of theequipped vehicle.
 12. The video mirror system of claim 11, wherein saidglobal positioning system provides altitude data and wherein altitudeinformation is displayed to the driver of the vehicle by one of saidcompass display and said video display screen.
 13. The video mirrorsystem of claim 11, wherein said global positioning system provides timedata and wherein time information is displayed to the driver of thevehicle by one of said compass display and said video display screen.14. A video mirror system for a vehicle, said video mirror systemcomprising: an interior rearview mirror assembly having a mirror housingand an electrochromic transflective reflective element; wherein saidmirror housing is adjustably mounted at an interior portion of thevehicle via a pivot mounting arrangement; wherein said transflectivereflective element comprises an electrochromic transflective reflectiveelement having a front substrate and a rear substrate and anelectrochromic medium disposed between said front and rear substrates;wherein said transflective reflective element comprises a transflectivemirror reflector disposed at a surface of said rear substrate, saidtransflective mirror reflector being partially transmissive of light andpartially reflective of light incident thereon, wherein saidtransflective mirror reflector is at least 15 percent transmissive tovisible light; wherein adjustment of said mirror housing via said pivotmounting arrangement adjusts a rearward field of view of saidtransflective reflective element when said interior rearview mirrorassembly is normally mounted in a vehicle equipped with said videomirror system; a video display screen disposed in said mirror housingand behind said transflective mirror reflector of said transflectivereflective element, wherein said video display screen comprises a liquidcrystal video display screen; wherein information displayed by saidvideo display screen is viewable by a driver of the equipped vehicleviewing through said transflective mirror reflector of saidtransflective reflective element when said video display screen isactivated and wherein, when said video display screen is not activated,the presence of said video display screen behind said transflectivemirror reflector of said transflective reflective element issubstantially not discerned by a driver of the equipped vehicle normallyviewing said transflective reflective element when operating theequipped vehicle; wherein said interior rearview mirror assemblycomprises at least one photosensor for detecting ambient light levels atthe vehicle, wherein said photosensor comprises a silicon photodiode;wherein said photosensor comprises a photosensor detector surface andwherein near infrared absorbing means are disposed in front of saidphotosensor detector surface of said photosensor for reducing theintensity of near infrared radiation incident thereon; a compass sensordisposed within said mirror housing and behind said transflectivereflective element, wherein said compass sensor adjusts in tandem withadjustment of the rearward field of view of said transflectivereflective element; compass circuitry responsive to said compass sensorfor determining a directional heading of the vehicle; a compass displayin the vehicle for displaying directional heading information to thedriver of equipped vehicle; and wherein said compass circuitry at leastpartially compensates for movement of said compass sensor caused byadjustment of said mirror housing via an algorithm processed by amicroprocessor.
 15. The video mirror system of claim 14, wherein saidnear infrared absorbing means comprises at least one of (a) a nearinfrared absorbing compound established in front of said photosensordetector surface of said photosensor, (b) a near infrared absorbingcompound established on or in a lens disposed in front of saidphotosensor detector surface of said photosensor, (c) a near infraredabsorbing filter disposed in front of said photosensor detector surfaceof said photosensor, and (d) a near infrared absorbing compoundestablished at one of (i) a filter disposed in front of said photosensordetector surface of said photosensor, (ii) a lens disposed in front ofsaid photosensor detector surface of said photosensor, (iii) a lightpipedisposed in front of said photosensor detector surface of saidphotosensor and (iv) a light conduit disposed in front of saidphotosensor detector surface of said photosensor.
 16. The video mirrorsystem of claim 15, wherein said compass display is at said interiorrearview mirror assembly and comprises a plurality of illuminationsources positioned behind said transflective reflective element, saidcompass circuitry energizing said illumination sources to conveydirectional heading information to the driver of the vehicle.
 17. Thevideo mirror system of claim 15 further comprising a global positioningsystem that is operable to determine a geographical location of theequipped vehicle.
 18. The video mirror system of claim 17, wherein saidglobal positioning system provides altitude data and wherein altitudeinformation is displayed to the driver of the vehicle by one of saidcompass display and said video display screen.
 19. The video mirrorsystem of claim 17, wherein said global positioning system provides timedata and wherein time information is displayed to the driver of thevehicle by one of said compass display and said video display screen.20. The video mirror system of claim 14, wherein said pivot mountingarrangement comprises one of (a) a single pivot mounting arrangement and(b) a double pivot mounting arrangement, and wherein an intensity ofsaid video display screen output is adjustable in response to an outputof said at least one photosensor.
 21. A video mirror system for avehicle, said video mirror system comprising: an interior rearviewmirror assembly having a mirror housing and an electrochromictransflective reflective element; wherein said mirror housing isadjustably mounted at an interior portion of the vehicle via a pivotmounting arrangement; wherein said transflective reflective elementcomprises an electrochromic transflective reflective element having afront substrate and a rear substrate and an electrochromic mediumdisposed between said front and rear substrates; wherein saidtransflective reflective element comprises a transflective mirrorreflector disposed at a surface of said rear substrate, saidtransflective mirror reflector being partially transmissive of light andpartially reflective of light incident thereon, wherein saidtransflective mirror reflector is at least 15 percent transmissive tovisible light; wherein adjustment of said mirror housing via said pivotmounting arrangement adjusts a rearward field of view of saidtransflective reflective element when said interior rearview mirrorassembly is normally mounted in a vehicle equipped with said videomirror system; a video display screen disposed in said mirror housingand behind said transflective mirror reflector of said transflectivereflective element, wherein said video display screen comprises a liquidcrystal video display screen; wherein information displayed by saidvideo display screen is viewable by a driver of the equipped vehicleviewing through said transflective mirror reflector of saidtransflective reflective element when said video display screen isactivated and wherein, when said video display screen is not activated,the presence of said video display screen behind said transflectivemirror reflector of said transflective reflective element issubstantially not discerned by a driver of the equipped vehicle normallyviewing said transflective reflective element when operating theequipped vehicle; wherein said interior rearview mirror assemblycomprises at least one photosensor for detecting ambient light levels atthe vehicle, wherein said photosensor comprises a silicon photodiode;wherein said photosensor comprises a photosensor detector surface andwherein near infrared absorbing means are disposed in front of saidphotosensor detector surface of said photosensor For reducing theintensity of near infrared radiation incident thereon; and wherein saidnear infrared absorbing means comprises at least one of (a) a nearinfrared absorbing compound established in front of said photosensordetector surface of said photosensor, (b) a near infrared absorbingcompound established on or in a lens disposed in front of saidphotosensor detector surface of said photosensor, (c) a near infraredabsorbing filter disposed in front of said photosensor detector surfaceof said photosensor, and (d) a near infrared absorbing compoundestablished at one of (i) a filter disposed in front of said photosensordetector surface of said photosensor, (ii) a lens disposed in front ofsaid photosensor detector surface of said photosensor, (iii) a lightpipedisposed in front of said photosensor detector surface of saidphotosensor and (iv) a light conduit disposed in front of saidphotosensor detector surface of said photosensor.
 22. The video mirrorsystem of claim 21, wherein said interior mirror assembly comprises acompass sensor.
 23. The video mirror system of claim 22, wherein saidcompass sensor is disposed within said mirror housing and behind saidtransflective reflective element, and wherein said compass sensoradjusts in tandem with adjustment of the rearward field of view of saidtransflective reflective element and wherein said system comprisescompass circuitry that at least partially compensates for movement ofsaid compass sensor caused by adjustment of said mirror housing via analgorithm processed by a microprocessor.
 24. The video mirror system ofclaim 21 further comprising a global positioning system that is operableto determine a geographical location of the equipped vehicle.
 25. Thevideo mirror system of claim 21, wherein said pivot mounting arrangementcomprises a double pivot mounting arrangement and wherein said compasssensor is disposed within said mirror housing and behind said reflectiveelement, and wherein said compass sensor adjusts in tandem withadjustment of the rearward field of view of said reflective element andwherein said mirror system comprises compass circuitry tat at leastpartially compensates for movement of said compass sensor caused byadjustment of said mirror housing via an algorithm processed by amicroprocessor.